INSULATION

CROSS-REFERENCE TO RELATED PATENT APPLICATION(S)

[0001] The present application claims priority to U.S. Provisional Patent Application No. 63/145,124 filed on February 3, 2021, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The technical field relates to plasma generation systems and methods and, more particularly, to such systems and methods providing enhanced electrical insulation.

BACKGROUND

[0003] Plasma sources and generators are used in various applications, such as nuclear fusion, neutron and high-energy photon generation, materials processing, and space propulsion. In particular, magnetic plasma confinement is one of several approaches to achieving controlled nuclear fusion for power generation. Many different types of plasma sources have been studied and developed over the years to achieve magnetic plasma confinement. In typical configurations, a plasma source operates by using the electric field generated by a high-voltage power supply to energize a gas into a plasma, and by relying on the Lorentz force to propel the plasma. Marshall or coaxial plasma guns are a common type of such plasma sources. A coaxial plasma gun generally includes a pair of coaxial electrodes defining an annular plasma chamber therebetween. The plasma formation process generally involves supplying gas in the plasma chamber and applying an electric potential difference between the electrodes to ionize the gas into a plasma, resulting in a radial electric current and an associated azimuthal magnetic field. The interaction between the electric current and the magnetic field produces a Lorentz force in the axial direction that pushes and accelerates the plasma axially forward along the plasma chamber.

SUMMARY

[0004] The present description generally relates to plasma generation systems and methods providing enhanced electrical insulation performance.

[0005] In accordance with an aspect, there is provided a plasma generation system including: a plasma source including a plasma chamber; a gas supply unit configured to supply process gas into the plasma chamber for the process gas to be energized into a plasma, the gas supply unit including: a gas supply line connecting the plasma chamber to a gas source configured to store the process gas; a gas supply valve disposed along the gas supply line and configured to control a flow of the process gas supplied into the plasma chamber; and a valve insulator disposed and configured to provide electrical insulation of the gas supply valve from the plasma source.

[0006] In some embodiments, the plasma generation system of claim 1, wherein the valve insulator is disposed along the gas supply line between the gas supply valve and the plasma chamber. In some embodiments, the valve insulator is an electrically insulating conduit segment configured to flow the process gas therethrough.

[0007] In some embodiments, the valve insulator is made of a glass material, a ceramic material, a glass-ceramic material, or any combination thereof. In some embodiments, the valve insulator is made of alumina, a borosilicate glass, a porcelain material, a boro-aluminosilicate glass-ceramic material, or any combination thereof.

[0008] In some embodiments, the gas supply valve is an electrically actuated valve. In some embodiments, the electrically actuated valve is a solenoid valve.

[0009] In some embodiments, the plasma source further includes a plasma power supply configured to couple energy into the plasma chamber and energize the process gas into the plasma.

[0010] In some embodiments, the plasma source further includes a first electrode and a second electrode arranged with respect to each other to enclose at least partially the plasma chamber. In some embodiments, the second electrode is configured to be electrically grounded, and the first electrode is configured to be electrically biased with respect to the second electrode. In some embodiments, the plasma source further includes an electrode insulator disposed and configured to provide electrical insulation between the first electrode and the second electrode. In some embodiments, the electrode insulator is made of a glass material, a ceramic material, a glass-ceramic material, or any combination thereof. In some embodiments, the electrode insulator is made of alumina, a borosilicate glass, a porcelain material, a boro-aluminosilicate glass-ceramic material, or any combination thereof. In some embodiments, the electrode insulator is disposed along the gas supply line, downstream of the valve insulator.

[0011] In some embodiments, the first electrode is an inner electrode, and the second electrode is an outer electrode surrounding the inner electrode to define an inter-electrode volume therebetween that defines at least part of the plasma chamber. In some embodiments, the outer electrode surrounds the inner electrode in a coaxial arrangement with respect to a longitudinal axis of the plasma source. In some embodiments, the gas supply line is coupled into the plasma chamber via one or more gas injection ports formed through the inner electrode. In some embodiments, the gas supply valve and the valve insulator are disposed outside the inner electrode. In some embodiments, the valve insulator is coupled to the inner electrode, and the gas supply line downstream of the valve insulator is formed by the inner electrode. In some embodiments, the gas supply valve and the valve insulator are disposed inside the inner electrode. In some embodiments, the gas supply line is coupled into the plasma chamber via one or more gas injection ports formed through the outer electrode.

[0012] In some embodiments, the gas supply unit further includes: at least one additional gas supply line connecting the plasma chamber to the gas source; at least one additional gas supply valve disposed along a respective one of the at least one additional gas supply line and configured to control at least one respective additional flow of the process gas supplied into the plasma chamber; and at least one additional valve insulator disposed and configured to provide electrical insulation of a respective one of the at least one additional gas supply line from the plasma source.

[0013] In some embodiments, the gas supply unit further includes a valve control circuit configured to control the gas supply valve to regulate the flow of the process gas along the gas supply line and into the plasma chamber, and a valve power supply configured to supply power to the valve control circuit.

[0014] In some embodiments, the plasma generation system further includes a vacuum system, the vacuum system including a vacuum chamber configured to enclose at least partially the plasma source. In some embodiments, the gas supply valve and the valve insulator are disposed inside the vacuum chamber. In some embodiments, the gas supply valve and the valve insulator are disposed outside the vacuum chamber.

[0015] In some embodiments, the process gas includes deuterium, tritium, hydrogen, or helium, or any combination thereof.

[0016] In accordance with another aspect, there is provided a plasma generation method including: controlling, with a gas supply valve, a flow of process gas along a gas supply line to supply the process gas into a plasma chamber of a plasma source; providing, with a valve insulator, electrical insulation of the gas supply valve from the plasma source; and supplying power to the plasma chamber to energize the process gas supplied into the plasma chamber into a plasma.

[0017] In some embodiments, the plasma generation method further includes disposing the valve insulator along the gas supply line between the gas supply valve and the plasma chamber. In some embodiments, the plasma generation method further includes providing the valve insulator is an electrically insulating conduit segment configured to flow the process gas therethrough.

[0018] In some embodiments, the valve insulator is made of a glass material, a ceramic material, a glass-ceramic material, or any combination thereof. In some embodiments, the valve insulator is made of alumina, a borosilicate glass, a porcelain material, a boro-aluminosilicate glass-ceramic material, or any combination thereof.

[0019] In some embodiments, the plasma generation method further includes providing the gas supply valve as an electrically actuated valve. In some embodiments, the electrically actuated valve is a solenoid valve.

[0020] In some embodiments, the plasma source further includes a first electrode and a second electrode arranged with respect to each other to enclose at least partially the plasma chamber. In some embodiments, the plasma generation method further includes electrically grounding the second electrode and electrically biasing the first electrode with respect to the second electrode. In some embodiments, the plasma generation method further includes providing an electrode insulator disposed and configured to provide electrical insulation between the first electrode and the second electrode. In some embodiments, providing the electrode insulator includes disposing the electrode insulator along the gas supply line, downstream of the valve insulator.

[0021] In some embodiments, the first electrode is an inner electrode, and the second electrode is an outer electrode surrounding the inner electrode to define an inter-electrode volume therebetween that defines at least part of the plasma chamber. In some embodiments, the plasma generation method further includes coupling the gas supply line into the plasma chamber via one or more gas injection ports formed through the inner electrode. In some embodiments, the plasma generation method further includes including disposing the gas supply valve and the valve insulator outside the inner electrode. In some embodiments, the plasma generation method further includes coupling the valve insulator to the inner electrode and using the inner electrode as the gas supply line downstream of the valve insulator. In some embodiments, the plasma generation method further includes disposing the gas supply valve and the valve insulator inside the inner electrode. In some embodiments, the plasma generation method further includes coupling the gas supply line into the plasma chamber via one or more gas injection ports formed through the outer electrode.

[0022] In some embodiments, the plasma generation method further includes: providing at least one additional gas supply line connecting the plasma chamber to the gas source; disposing at least one additional gas supply valve along a respective one of the at least one additional gas supply line; controlling, with the at least one additional gas supply valve, at least one respective additional flow of the process gas supplied into the plasma chamber; and providing at least one additional valve insulator configured to provide electrical insulation of a respective one of the at least one additional gas supply line from the plasma source.

[0023] In some embodiments, the plasma generation method further includes enclosing at least part of the plasma source inside a vacuum chamber. [0024] In some embodiments, the process gas includes deuterium, tritium, hydrogen, or helium, or any combination thereof.

[0025] In some embodiments, the step of supplying power to the plasma chamber is initiated after initiating the step of supplying the process gas into the plasma chamber. In some embodiments, the step of supplying power to the plasma chamber is initiated before or at the same time as initiating the step of supplying the process gas into the plasma chamber.

[0026] In accordance with another aspect, there is provided a plasma generation method including: supplying, with a gas supply unit, process gas into a plasma chamber of a plasma source, the gas supply unit including a gas supply line connecting the plasma chamber to a gas source configured to store the process gas, and a gas supply valve disposed along the gas supply line and configured to control a flow of the process gas supplied into the plasma chamber; providing, with a valve insulator, electrical insulation of the gas supply valve from the plasma source; and energizing the process gas supplied into the plasma chamber into a plasma.

[0027] In accordance with another aspect, there is provided a plasma generation system including: a plasma source including a plasma chamber; and a gas supply unit configured to supply process gas into the plasma chamber to be energized into a plasma, the gas supply unit including: a gas supply valve configured to control a flow of the process gas from a gas source to the plasma chamber; a gas supply line connecting the gas supply valve with the plasma chamber; and a valve insulator disposed along the gas supply line and configured to provide electrical insulation of the gas supply valve from the plasma source.

[0028] In some embodiments, the valve insulator is disposed along the gas supply line.

[0029] In some embodiments, the plasma source includes a plasma power supply configured to couple energy into the plasma chamber and energize the process gas into the plasma.

[0030] In some embodiments, the plasma source includes a first electrode and a second electrode arranged with respect to each other to enclose at least partially the plasma chamber. In some embodiments, the second electrode is disposed around the first electrode to define a space therebetween that defines at least partially the plasma chamber. In such embodiments, the first electrode may be referred to as an inner electrode and the second electrode may be referred to as an outer electrode. In some embodiments, the gas supply line is coupled into the plasma chamber via one or more gas injection ports formed through the inner electrode or the outer electrode. In some embodiments, the second electrode is disposed around the first electrode in a coaxial arrangement. In such embodiments, the plasma source may be referred to as a Marshall or coaxial plasma gun. In some embodiments, the first and second electrodes are not disposed in a coaxial arrangement.

[0031] In some embodiments, the plasma source includes an electrode insulator disposed and configured to provide electrical insulation between the first electrode and the second electrode. In some embodiments, the electrode insulator is disposed along the gas supply line downstream of the valve insulator.

[0032] In some embodiments, the gas supply valve is an electrically actuated valve, such as a solenoid valve or the like.

[0033] In some embodiments, the valve insulator is made of a glass, ceramic, or glass-ceramic material. More specific examples of possible materials for the valve insulator include, to name a few, alumina, borosilicate glass, porcelain, and MACOR®.

[0034] In some embodiments, the gas supply unit includes a single gas supply valve. In other embodiments, the gas supply unit includes multiple gas supply valves coupled to the plasma chamber via one or more gas supply lines and electrically insulated from the plasma source by one or more valve insulators.

[0035] In some embodiments, the plasma generation system includes a vacuum system having a vacuum chamber that encloses at least partially the plasma source.

[0036] In accordance with another aspect, there is provided a plasma generation system including: a plasma source including: an inner electrode; an outer electrode disposed around the inner electrode; a plasma chamber formed at least partially between the inner electrode and the outer electrode; and an electrode insulator disposed and configured to provide electrical insulation between the inner electrode and the outer electrode; and a gas supply unit configured to supply process gas into the plasma chamber to be energized into a plasma by application of an electric potential difference between the inner electrode and the outer electrode, the gas supply unit including: a gas supply valve configured to control a flow of the process gas from a gas source to the plasma chamber; a gas supply line connecting the gas supply valve with the plasma chamber via at least one gas injection port formed in either one of the inner electrode and the outer electrode; and a valve insulator disposed along the gas supply line and configured to provide electrical insulation of the gas supply valve from the plasma source.

[0037] In some embodiments, the electrode insulator is disposed along the gas supply line between the valve insulator and the gas injection port.

[0038] In accordance with another aspect, there is provided a plasma generation method including: supplying, from a gas supply unit, process gas into a plasma chamber of a plasma source, the gas supply unit including a gas supply valve configured to control a flow of the process gas and a gas supply line connecting the gas supply valve with the plasma chamber; providing, with a valve insulator, electrical insulation of the gas supply valve from the plasma source; and energizing the process gas supplied to the plasma chamber into a plasma.

[0039] In some embodiments, the method includes disposing the valve insulator along the gas supply line.

[0040] Other method and process steps may be performed prior, during, or after the steps described herein. The order of one or more steps may also differ, and some of the steps may be omitted, repeated, and/or combined, as the case may be.

[0041] Other objects, features, and advantages of the present description will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the appended drawings. Although specific features described in the above summary and in the detailed description below may be described with respect to specific embodiments or aspects, it should be noted that these specific features may be combined with one another unless stated otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Fig. 1 is a flow diagram of a plasma generation method, in accordance with an embodiment.

[0043] Fig. 2 is a schematic longitudinal cross-sectional view of a plasma generation system, in accordance with an embodiment.

[0044] Fig. 3 is a schematic longitudinal cross-sectional view of a plasma generation system, in accordance with another embodiment. [0045] Fig. 4 is a schematic longitudinal cross-sectional view of a plasma generation system, in accordance with another embodiment.

[0046] Fig. 5 is a schematic cross-sectional view of a plasma generation system, in accordance with another embodiment.

DETAILED DESCRIPTION

[0047] In the present description, similar features in the drawings have been given similar reference numerals. To avoid cluttering certain figures, some elements may not be indicated if they were already identified in a preceding figure. The elements of the drawings are not necessarily depicted to scale, since emphasis is placed on clearly illustrating the elements and structures of the present embodiments. Furthermore, positional descriptors indicating the location and/or orientation of one element with respect to another element are used herein for ease and clarity of description. Unless otherwise indicated, these positional descriptors should be taken in the context of the figures and should not be considered limiting. Such spatially relative terms are intended to encompass different orientations in the use or operation of the present embodiments, in addition to the orientations exemplified in the figures. Furthermore, when a first element is referred to as being “on”, “above”, “below”, “over”, or “under” a second element, the first element can be either directly or indirectly on, above, below, over, or under the second element, respectively, such that one or multiple intervening elements may be disposed between the first element and the second element.

[0048] The terms “a”, “an”, and “one” are defined herein to mean “at least one”, that is, these terms do not exclude a plural number of elements, unless stated otherwise.

[0049] The term “or” is defined herein to mean “and/or”, unless stated otherwise.

[0050] The expressions “at least one of X, Y, and Z” and “one or more of X, Y, and Z”, and variants thereof, are understood to include X alone, Y alone, and Z alone, as well as any combination of X, Y, and Z.

[0051] Terms such as “substantially”, “generally”, and “about”, which modify a value, condition, or characteristic of a feature of an exemplary embodiment, should be understood to mean that the value, condition, or characteristic is defined within tolerances that are acceptable for the proper operation of this exemplary embodiment for its intended application or that fall within an acceptable range of experimental error. In particular, the term “about” generally refers to a range of numbers that one skilled in the art would consider equivalent to the stated value (e.g., having the same or an equivalent function or result). In some instances, the term “about” means a variation of ±10% of the stated value. It is noted that all numeric values used herein are assumed to be modified by the term “about”, unless stated otherwise. The term “between” as used herein to refer to a range of numbers or values defined by endpoints is intended to include both endpoints, unless stated otherwise.

[0052] The term “based on” as used herein is intended to mean “based at least in part on”, whether directly or indirectly, and to encompass both “based solely on” and “based in part on”. In particular, the term “based on” may also be understood as meaning “depending on”, “representative of’, “indicative of’, “associated with”, “relating to”, and the like.

[0053] The terms “match”, “matching”, and “matched” refer herein to a condition in which two elements are either the same or within some predetermined tolerance of each other. That is, these terms are meant to encompass not only “exactly” or “identically” matching the two elements but also “substantially”, “approximately”, or “subjectively” matching the two elements, as well as providing a higher or best match among a plurality of matching possibilities.

[0054] The terms “connected” and “coupled”, and derivatives and variants thereof, refer herein to any connection or coupling, either direct or indirect, between two or more elements, unless stated otherwise. For example, the connection or coupling between elements may be mechanical, optical, electrical, magnetic, thermal, chemical, logical, fluidic, operational, or any combination thereof.

[0055] The term “concurrently” refers herein to two or more processes that occur during coincident or overlapping time periods. The term “concurrently” does not necessarily imply complete synchronicity and encompasses various scenarios including time-coincident or simultaneous occurrence of two processes; occurrence of a first process that both begins and ends during the duration of a second process; and occurrence of a first process that begins during the duration of a second process, but ends after the completion of the second process.

[0056] The present description generally relates to plasma generation systems and methods with enhanced electrical insulation of gas supply valves. The techniques disclosed herein may be used in various fields and applications, including nuclear fusion, neutron and high-energy photon generation, materials processing, and space propulsion.

[0057] Referring to Fig. 1, there is illustrated a flow diagram of a plasma generation method 200, in accordance with an embodiment. The method 200 of Fig. 1 may be implemented in a plasma generation system 100 such as the ones depicted in Figs. 2 to 4, or another suitable plasma generation system. The method 200 of Fig. 1 includes a step 202 of controlling, with a gas supply valve, a flow of process gas along a gas supply line to supply the process gas into a plasma chamber of a plasma source. The method 200 can also include a step 204 of providing, with a valve insulator, electrical insulation of the gas supply valve from the plasma source, and a step 206 of supplying power to the plasma chamber to energize the process gas supplied into the plasma chamber into a plasma. It is noted that the terms “upstream” and “downstream” refer herein to the direction of the flow of the process gas from a gas source storing the process gas to the plasma chamber into which the process gas supplied.

[0058] More detail regarding these steps and other possible steps of the plasma generation method 200 are provided below.

[0059] Referring to Fig. 2, there is illustrated a schematic longitudinal cross-sectional view of a plasma generation system 100 in accordance with an embodiment. In the illustrated embodiment, the plasma generation system 100 has a coaxial plasma gun configuration.

[0060] In some implementations, the plasma generation system disclosed herein may be used to generate a plasma for injection inside the reaction chamber of a fusion reactor, for example, a Z-pinch- based fusion reactor. In such implementations, the plasma can be generated by the plasma generation system outside the reaction chamber, and then be injected inside the reaction chamber to be energized and compressed at fusion conditions, for example, by forming and sustaining a Z-pinch plasma inside the reaction chamber. Non-limiting examples of external plasma sources in which the valve insulation techniques disclosed herein could be implemented are described in co-assigned International Patent Application No. PCT/US2021/062830, filed on December 10, 2021, co-assigned International Patent Application No. PCT/US2022/012502, filed on January 14, 2022, and co-assigned U.S. Provisional Patent Application No. 63/262,451 fded on October 13, 2021, the contents of these documents being incorporated herein by reference in their entirety. In other implementations, the plasma generation system disclosed herein can be used as a fusion reactor itself, rather than as an external source of plasma coupled to the reaction chamber of a fusion reactor. Non-limiting examples of fusion reactors in which the valve insulation techniques disclosed herein could be implemented are described in the following doctoral dissertation: Golingo, Raymond, Formation of a Sheared Flow Z-Pinch (University of Washington, 2003), the contents of which are incorporated herein by reference in their entirety.

[0061] The plasma generation system 100 of Fig. 2 generally includes a plasma source 102 and a gas supply unit 104. The plasma source 102 includes a plasma chamber 106, and the gas supply unit 104 is configured to supply a process gas 108 into the plasma chamber 106 to be energized into a plasma 110. The gas supply unit 104 includes a gas supply line 112 connecting the plasma chamber 106 to a gas source 114 configured to store the process gas 108, a gas supply valve 116 disposed along the gas supply line 112 and configured to control a flow of the process gas 108 supplied into the plasma chamber 106, and a valve insulator 118 disposed and configured to provide electrical insulation of the gas supply valve 116 from the plasma source 102.

[0062] More details regarding the structure, configuration, and operation of these components and other possible components of the plasma generation system 100 are provided below. It is appreciated that Fig. 2 is a simplified schematic representation that illustrates certain features and components of the plasma generation system 100, such that additional features and components that may be useful or necessary for its practical operation may not be specifically depicted. Non-limiting examples of such additional features and components can include, to name a few, power supplies, electrical connections, gas sources, gas supply lines, pressure and flow control devices (e.g., pumps, valves, regulators, restrictors), operation monitoring and diagnostic devices (e.g., sensors), processors and controllers, and other standard hardware and equipment.

[0063] In the embodiment illustrated in Fig. 2, the plasma source 102 is configured as a coaxial plasma gun. Coaxial plasma guns are electromagnetic plasma generators generally configured to operate by using the electric field generated by a high-voltage power supply to energize a gas into a plasma, and by relying on the Lorentz force to propel the plasma toward an outlet of the plasma gun. However, it is appreciated that many plasma formation and generation techniques exist, notably in fusion power applications, and may be used in the embodiments disclosed herein to form the plasma 110 from the process gas 108 supplied by the gas supply unit 104. As such, the plasma source 102 depicted in Fig. 2 is provided by way of example only, and various types of plasma sources are contemplated for use in other embodiments. Non-limiting examples of such possible plasma sources include, to name a few, gas injected washer plasma guns; plasma thrusters, for example, Hall effect thrusters and MHD thrusters; high-power helicon plasma sources; RF plasma sources; and laser-based plasma sources. The theory, configuration, operation, and application of plasma sources are generally known in the art and need not be described in detail herein other than to facilitate an understanding of the present techniques.

[0064] In the illustrated embodiment, the plasma source 102 includes a first electrode 120 and a second electrode 122 arranged with respect to each other to enclose at least partially the plasma chamber 106. The first electrode 120 and the second electrode 122 can each be made of any suitable electrically conductive material, such as various metals and metal alloys. Non-limiting examples include, to name a few, tungsten-coated copper and graphite. In the arrangement depicted in Fig. 2, the first electrode 120 is an inner electrode and the second electrode 122 is an outer electrode surrounding the inner electrode in a coaxial arrangement with respect to a longitudinal axis 124 of the plasma source 102. The plasma chamber 106 is formed at least partially by the annular inter-electrode volume extending radially between the inner electrode 120 and the outer electrode 122. In the illustrated embodiment, the inner electrode 120 and the outer electrode 122 each have an elongated configuration along the longitudinal axis 124. The inner electrode 120 extends between a front end 126 and a rear end 128, and the outer electrode 122 extends between a front end 130 and a rear end 132.

[0065] In the illustrated embodiment, the inner electrode 120 and the outer electrode 122 both have a substantially cylindrical configuration, with a circular cross-section transverse to the longitudinal axis 124. However, various other electrode configurations may be used in other embodiments. Nonlimiting examples include, to name a few, non-coaxial arrangements (see, e.g., Fig. 5), non-circularly symmetric transverse cross-sections, three-electrode arrangements, and the like. In some embodiments, the inner electrode 120 may have a length ranging from about 75 mm to about one or a few meters and a radius ranging from about 2 mm to about 1 m, while the outer electrode 122 may have a length ranging from about 75 mm to about 6 m, a radius ranging from about 12 mm to about 2 mm, and a wall thickness ranging from about 2.5 mm to about 12 mm, although other electrode dimensions may be used in other embodiments. Depending on the application, the inner electrode 120 may have a full configuration or a hollow configuration. In the embodiment of Fig. 2, the front end 126 of the inner electrode 120 is axially aligned with the front end 130 of the outer electrode 122, and the rear end 128 of the inner electrode 120 projects longitudinally rearwardly beyond the rear end 132 of the outer electrode 122. However, other configurations are possible in other embodiments. For example, in some embodiments, the front end 130 of the outer electrode 122 can project longitudinally forwardly beyond the front end 126 of the inner electrode 120. In such embodiments, the plasma chamber 106 can include a first region having an annular cross-section, which is radially enclosed between the inner electrode 120 and the outer electrode 122, and a second region having a circular cross-sectional shaped, which is radially enclosed by the portion of the outer electrode 122 that projects longitudinally beyond the front end 126 of the inner electrode 120. Non-limiting examples of such plasma chamber 106 are disclosed in co-assigned International Patent Application No. PCT/US2021/062830, filed on December 10, 2021, and in the following doctoral dissertation: Golingo, Raymond, Formation of a Sheared Flow Z-Pinch (University of Washington, 2003). It is appreciated that the size, shape, composition, structure, and arrangement of the inner electrode 120 and the outer electrode 122 can be varied depending on the application.

[0066] Referring still to Fig. 2, the plasma source 102 also includes at least one electrode insulator 134 disposed between the inner electrode 120 and the outer electrode 122. The electrode insulator 134 is configured to provide electrical insulation between the inner electrode 120 and the outer electrode 122 so as to prevent or help prevent unwanted charge buildup and other undesirable electrical phenomena that could adversely affect the operation of the plasma source 102. In the illustrated embodiment, the electrode insulator 134 has an annular cross-sectional shape and is disposed radially between the inner electrode 120 and the outer electrode 122 near the rear ends 128, 132 thereof. The electrode insulator 134 can be made of any suitable electrically insulating material. Non-limiting examples of such possible materials include glass, ceramic, and glass-ceramic materials. More specific examples of possible materials include, to name a few, alumina, borosilicate glass, porcelain, and MACOR® (a machinable boro-aluminosilicate glass-ceramic material by Corning Inc.). It is appreciated that the at least one electrode insulator 134 may be of varying sizes, shapes, compositions, locations, and configurations depending on the application.

[0067] Referring still to Fig. 2, the plasma chamber 106 is configured to receive the process gas 108 from the gas supply unit 104. The process gas 108 may be any suitable gas or gas mixture capable of being energized into a plasma 110 by the plasma source 102. Depending on the application, the process gas 108 can be a neutral gas or gas mixture, or a weakly ionized gas or gas mixture. For example, in fusion applications, the process gas 108 may be deuterium gas or a gas mixture containing deuterium and tritium, or may contain other fusion reactants. Other mixtures may include hydrogen or helium.

[0068] The process gas 108 supplied into the plasma chamber 106 is ionized into a plasma 110 by application of a voltage between the inner electrode 120 and the outer electrode 122. For this purpose, the plasma source 102 in Fig. 2 includes a plasma power supply 136 configured to supply power to the plasma chamber 106 to energize the process gas 108 into the plasma 110. The term “power supply” refers herein to any device or combination of devices configured to supply electrical power into a form usable by another device or combination of devices. It is appreciated that while the plasma power supply 136 is depicted as a single entity in Fig. 2 for illustrative purposes, the term “power supply” should not be construed as being limited to a single power supply and, accordingly, in some embodiments the plasma power supply 136 may include a plurality of power supply units. The plasma power supply 136 is connected to the inner electrode 120 and the outer electrode 122 via appropriate electrical connections. In the illustrated embodiment, the inner electrode 120 is electrically (either positively or negatively) biased and the outer electrode 122 is electrically grounded. However, the opposite configuration may also be used, in which the inner electrode 120 is electrically grounded and the outer electrode 122 is electrically (either positively or negatively) biased. In yet other embodiments, neither the inner electrode 120 nor the outer electrode 122 may be electrically grounded.

[0069] In some embodiments, the plasma power supply 136 may be a pulsed-DC power supply and may include an energy source (e.g., a capacitor bank, such as in Fig. 7), a switch (e.g., a spark gap, an ignitron, or a semiconductor switch), and a pulse shaping network (including, e.g., inductors, resistors, diodes, and the like). Depending on the application, the plasma power supply 136 may be voltage- controlled or current-controlled. In other embodiments, other suitable types of power supplies may be used, including DC and AC power supplies. Non-limiting examples include, to name a few, DC grids, voltage source converters, flywheel power supplies, and homopolar generators. The plasma power supply 136 is configured to supply power to the plasma source 102 in order to apply a voltage between the inner electrode 120 and the outer electrode 122 to generate an electric field across the plasma chamber 106. The electric field is configured to ionize and break down the process gas 108, thereby forming the plasma 110. In some embodiments, the voltage applied between the inner electrode 120 and the outer electrode 122 may range from about 750 V to about 5 kV, although other voltage values may be used in other embodiments. It is appreciated that the configuration and the operation of the plasma power supply 136 may be adjusted to favor the breakdown of the process gas 108 supplied in the plasma chamber 106 and to control the parameters of the plasma 110 to be formed. For example, in some embodiments, the plasma 110 generated in the plasma chamber 106 may have the following properties and parameters: an electron temperature ranging from about 1 eV to about 100 eV, an ion temperature ranging from about 1 eV to about 100 eV, an electron density ranging from about 10 ¹³ cm ³ to about 10 ¹⁶ cnr . an ion density ranging from about 10 ¹³ cm ³ to about 10 ¹⁶ cm ', and a degree of ionization ranging from about 50% to about 100%. Depending on the application, the plasma 110 may be magnetized or unmagnetized.

[0070] Referring still to Fig. 2, the plasma generation system 100 can include a vacuum system 138. The vacuum system 138 includes a vacuum chamber 140, for example, a stainless steel pressure vessel or tank. The vacuum chamber 140 houses, at least partially, various components of the plasma source 102, including the inner electrode 120, the outer electrode 122, and the plasma chamber 106. For example, in the illustrated embodiment, the inner electrode 120 is partially contained in the vacuum chamber 140 (i.e., its rear portion projects outside the vacuum chamber 140), and the outer electrode is fully contained in the vacuum chamber. Other configurations are contemplated in other embodiments. In some embodiments, the vacuum chamber 140 is electrically grounded and/or at the same electric potential as either the inner electrode 120 or the outer electrode 122, but these are not requirements. In some embodiments, the insertion of the plasma source 102 inside the vacuum chamber 140 may involve mounting the plasma source 102 to a vacuum flange 142 (e.g., a ConFlat™ flange) and mating the vacuum flange 142 to a flanged port 144 (e.g., an end wall flanged port) of the vacuum chamber 140. Other configurations are contemplated in other embodiments. The vacuum system 138 may also include a pressure control unit 146 configured to control the operating pressure inside the vacuum chamber 140. In some embodiments, the pressure inside the vacuum chamber 140 may range from about 10 ^x Torr to about 1 Torr, although other ranges of pressure may be used in other embodiments.

[0071] Referring still to Fig. 2, the gas supply unit 104 is configured to supply the process gas 108 into the plasma chamber 106 for the process gas 108 to be energized into the plasma 110 as a result of the voltage applied by the plasma power supply 136 between the inner electrode 120 and the outer electrode 122. The gas supply unit 104 includes or is coupled to the gas source 114 configured to store the process gas 108. The gas source 114 can be embodied by a gas storage tank or any suitable pressurized gas dispensing container. The gas supply unit 104 also includes the gas supply line 112, the gas supply valve 116 and the valve insulator 118 introduced above, which are described in greater detail below.

[0072] The gas supply line 112 is configured to provide fluid communication between the gas source 114 and the interior of the plasma chamber 106. The gas supply line 112 can be embodied by various types of gas conduits (e.g., pipes or tubes of any suitable size, shape, configuration, and composition) capable of flowing gas therealong between the gas source 114 and the plasma chamber 106. It is appreciated that different segments of the gas supply line 112 may have different properties (e.g., in terms of size, shape, configuration, composition, and the like). The gas supply line 112 terminates into the plasma chamber 106 via two gas injection ports 148 formed through the circumferential wall of the inner electrode 120 at the same axial position but at opposite azimuthal positions with respect to the longitudinal axis 124. It is appreciated that the gas injection port configuration illustrated in Fig. 2 is provided by way of example only, and that the number and the arrangement of the gas injection port(s) 148 can be varied to suit the needs of a particular application. It is also appreciated that various other configurations and arrangements are contemplated for the gas supply line 112. Depending on the application, the gas supply line 112 may be coupled into the plasma chamber 106 via one or more gas injection ports formed only through the inner electrode 120 (see, e.g., Figs. 2 and 4), only through the outer electrode 122 (see, e.g., Fig. 3), through both the inner electrode 120 and the outer electrode 122, through an end wall of the vacuum chamber 140, or at any other suitable locations of the plasma source 102. Depending on the application, the operation of introducing the process gas 108 into the plasma chamber 106 can be initiated before, at the same time as, or after initiating the operation of activating the plasma power supply 136 to apply the voltage between the inner electrode 120 and the outer electrode 122.

[0073] The gas supply valve 116 is configured to control a flow of the process gas 108 along the gas supply line 112, from the gas source 114 to the plasma chamber 106. The gas supply valve 116 may be embodied by a variety of electrically actuated valves, such as a solenoid valve, a ball valve, a butterfly valve, a diaphragm valve, a plug valve, a piezoelectric valve, a mass flow controller, and the like. It is appreciated that the term “electrically actuated valve” is intended to include all forms of electromagnetically, electromechanically, electro-pneumatically, electro-hydraulically, and other forms of electrically actuated valves. For example, in the embodiment illustrated in Fig. 2, the gas supply valve 116 is a solenoid valve, and the gas supply unit 104 includes a valve control circuit 150 configured to control the gas supply valve 116 to regulate the flow of the process gas along the gas supply line 112 and into the plasma chamber 106, and a valve power supply 152 configured to supply power to the valve control circuit 150. It is appreciated that the theory, configuration, operation, and application of solenoid valves and solenoid valve control circuits are generally known in the art, including in the field of plasma generation systems and methods, and need not be described in detail herein other than to facilitate an understanding of the presented techniques. It is also appreciated that the gas supply unit 104 may also include various additional flow control devices (not shown), for example, pumps, regulators, and restrictors, configured to control the process gas flow rate and pressure, tn particular, various gas injection configurations for supplying the process gas 108 into the plasma chamber 106 are contemplated by the present techniques.

[0074] Referring still to Fig. 2, the valve insulator 118 is disposed along the gas supply line 112, downstream of the gas supply valve 116 but outside the vacuum chamber 140. It is appreciated that the valve insulator 118 is a component distinct and separate from the gas supply valve 116. In the illustrated embodiment, the valve insulator 118 is embodied by an electrically insulating conduit segment that extends between a first portion 154 and a second portion 156 of the gas supply line 112. The first portion 154 is embodied by a gas conduit (e.g., an electrically conducting pipe or tube) having an upstream end coupled to the gas supply valve 116 and a downstream end coupled to an upstream end of the valve insulator 118. The second portion 156 is embodied by a rear portion of the inner electrode 120 and has an upstream end, corresponding to the rear end 128 of the inner electrode 120, coupled to a downstream end of the valve insulator 118 and a downstream end terminating at the gas injection ports 148 formed through the inner electrode 120 and leading to the plasma chamber 106.

[0075] The valve insulator 118 is configured to provide electrical insulation of the gas supply valve 116 from the plasma source 102. The valve insulator 118 can be made of any suitable electrically insulating material. Non-limiting examples of such possible materials include glass, ceramic, and glassceramic materials. More specific examples of possible materials include, to name a few, alumina, borosilicate glass, porcelain, and MACOR®. In some embodiments, the valve insulator 118 may advantageously be made of a material having a high mechanical strength, a good machinability, and/or good thermal insulating properties. As noted above, the valve insulator 118 depicted in Fig. 1 is embodied by a short conduit segment (e.g., having a length ranging from about 5 mm to about 50 mm) made of an electrically insulating material. It is appreciated, however, that the valve insulator 118 may be of varying sizes, shapes, compositions, locations, and configurations depending on the application. It is noted that although the gas supply unit 104 depicted in Fig. 2 includes a single valve insulator 118, other embodiments may include multiple valve insulators disposed along the gas supply line 112 (e.g., at longitudinally spaced-apart intervals one from the other) between the gas supply valve 116 and the gas injection ports 148. It is also noted that, in some embodiments, the valve insulator 118 may be disposed not along the gas supply line 112, as in Figs. 2 to 4, but at another location of the plasma generation system 100 where the valve insulator 118 can provide electrical insulation between the gas supply valve 116 and the plasma source 102, for at example at the gas injection port.

[0076] It is appreciated that the plasma generation system 100 illustrated in Fig. 2 includes two different insulators: the electrode insulator 134, which is configured to provide electrical insulation between the inner electrode 120 and the outer electrode 122, and the valve insulator 118, which is configured to provide electrical insulation to the gas supply valve 116 from the plasma source 102. The provision of the valve insulator 118 can ensure or help ensure the integrity and performance characteristics of the gas supply valve 116 during operation of the plasma generation system 100. The valve insulator 118 may be configured to prevent or reduce the likelihood of dielectric breakdown or other electrical failure (e.g., spurious valve opening caused by noise) in the gas supply valve 116 (e.g., in the internal insulation structure provided within the body of the gas supply valve 116). For example, in operation of the plasma generation system 100 illustrated in Fig. 2, the inner electrode 120 is electrically biased, generally to relatively high voltages (e.g., larger than a few kV), while the outer electrode 122 is electrically grounded, as is the vacuum chamber 140. Since part of the gas supply line 112 downstream of the gas supply valve 116 extends within the electrically biased inner electrode 120, there are risks in the absence of the valve insulator 118 that high voltages be induced between the inner electrode 120 and the gas supply valve 116 (i.e., the voltages associated with the plasma source 102 would be applied to the gas supply valve 116 without the provision of the valve insulator 118). Such high voltages can be higher than the maximum voltages that the gas supply valve 116 is configured to withstand, and can therefore damage, degrade, wear, or unduly stress electrical components of the gas supply valve 116 (e.g., by causing arcing inside the valve body). This in turn can adversely affect the capability of the gas supply valve 116 to control the flow of the process gas 108 supplied into the plasma chamber 106. The provision of the valve insulator 118 along the gas supply line 112, between the gas supply valve 116 and electrically biased components of the plasma source 102 (e.g., the inner electrode 120 in the embodiment of Fig. 2) can eliminate or at least reduce these risks and their unwanted or detrimental impacts on the operation of the gas supply valve 116. It is further appreciated that the provision of the valve insulator 118 may also be advantageous or required in implementations where the gas supply valve 116 is provided close to electrically grounded components of the plasma source 102. This is because in such configurations the gas supply valve 116 may also be prone to issues due to an insufficient electrical insulation. Such issues may be related, for example, to the finite inductance of grounding cables.

[0077] It is noted that although the gas supply unit 104 depicted in Fig. 2 includes a single gas source 114, a single gas supply line 112, a single supply valve 116, for simplicity, this is not a requirement. In particular, other embodiments may include multiple gas sources, multiple gas supply lines, and/or multiple supply valves, where each supply valve may be insulated from the plasma source by the provision of one or more valve insulators.

[0078] Referring to Fig. 3, there is illustrated another embodiment of a plasma generation system 100. The embodiment of Fig. 3 shares several features with the embodiment of Fig. 2, which will not be described in detail again other than to highlight differences between them. The plasma generation system 100 of Fig. 3 generally includes a plasma source 102 and a gas supply unit 104. The plasma source 102 includes a plasma chamber 106 and is configured to form a plasma 110 by energizing a process gas 108 supplied into the plasma chamber 106 by the gas supply unit 104. The plasma source 102 includes an inner electrode 120, an outer electrode 122 surrounding the inner electrode 120, and a plasma chamber 106 formed at least partially in the inter-electrode volume defined between the inner electrode 120 and the outer electrode 122. The inner electrode 120 and the outer electrode 122 have an elongated configuration along a longitudinal axis 124 of the plasma source 102. The inner electrode 120 has a substantially cylindrical configuration, while the outer electrode 122 has a substantially tubular configuration and encloses the inner electrode 120 in a coaxial arrangement with respect to the longitudinal axis 124. The inner electrode 120 and the outer electrode 122 may each be made of any suitable electrically conductive material, such as various metals and metal alloys. The plasma chamber 106 has an annular cross-sectional shape and is configured to receive the process gas 108 from the gas supply unit 104. The process gas 108 may be any suitable gas or gas mixture capable of being energized into the plasma 110. In some embodiments, the process gas 108 may include fusion reactants.

[0079] The plasma source 102 also includes a plasma power supply 136 configured to couple energy into the plasma chamber 106 to energize the process gas 108 into the plasma 110. The plasma power supply 136 is connected to the inner electrode 120 and the outer electrode 122 via appropriate electrical connections. In some embodiments, the inner electrode 120 is electrically biased and the outer electrode 122 is electrically grounded, although different configurations may be used in other embodiments. The plasma power supply 136 is configured to apply a voltage between the inner electrode 120 and the outer electrode 122 to generate an ionizing electric field across the plasma chamber 106. The ionizing electric field is configured to ionize and break down the process gas 108, thereby forming the plasma 110. The plasma source 102 further includes an electrode insulator 134 disposed radially between the inner electrode 120 and the outer electrode 122. The electrode insulator 134 is configured to provide electrical insulation between the inner electrode 120 and the outer electrode 122. As in the embodiment of Fig. 2, the electrode insulator 134 can be made of any suitable electrically insulating material. It is appreciated that the electrode insulator 134 may be of varying sizes, shapes, locations, and configurations depending on the application.

[0080] The plasma generation system 100 further includes a vacuum system 138. The vacuum system 138 includes a vacuum chamber 140, for example, a stainless steel pressure vessel or tank. The vacuum chamber 140 houses at least partially various components of the plasma source 102, including the inner electrode 120, the outer electrode 122, and the plasma chamber 106. In some embodiments, the vacuum chamber 140 is electrically grounded and at the same electric potential as either the inner electrode 120 or the outer electrode 122. The plasma source 102 may be inserted inside the vacuum chamber 140 by mounting the plasma source 102 to a vacuum flange 142 (e.g., a ConFlat™ flange) and mating the vacuum flange 142 to a flanged port 144 (e.g., an end wall flanged port) of the vacuum chamber 140. Other configurations are contemplated in other embodiments.

[0081] Referring still to Fig. 3, the gas supply unit 104 is configured to supply the process gas 108 into the plasma chamber 106 to be energized into the plasma 110. The gas supply unit 104 may include or be coupled to a gas source 114 configured to store the process gas 108. The gas supply unit 104 also includes first and second gas supply lines 112i, 112 ₂ , each of which configured to provide fluid communication between the gas source 114 and the plasma chamber 106. Depending on the application, the gas supply lines 112i, 112 ₂ may be connected to the same gas source 114, as depicted in Fig. 3, or to different gas sources. The gas supply unit 104 further includes first and second gas supply valves 116i, 116 ₂ configured to control a flow of the process gas 108 along the first and second gas supply lines 112i 112 ₂ , respectively, from the gas source 114 to the plasma chamber 106. The gas supply valves 116i, 116 ₂ may each be embodied by a variety of electrically actuated valves, as noted above with respect to the embodiment of Fig. 2. In the embodiment of Fig. 3, the first and second gas supply valves 116i, 116 ₂ are both solenoid valves, each of which electrically connected to a respective valve driving circuit 150i, 150 ₂ and a respective valve power supply 152i, 152 ₂ . Depending on the application, the first and second gas supply valves 116i, 116 ₂ may or may not be identical to each other. Each of the two gas supply lines 112i, 112 ₂ extends along a path that passes successively through the outer wall of the vacuum chamber 140 and the outer electrode 122, and that terminates into the plasma chamber 106 via a respective gas injection port 148i, 148 ₂ formed through the outer electrode 122. In the illustrated embodiment, the two gas supply lines 112i, 112 ₂ are disposed at the same axial position but at opposite azimuthal positions with respect to the longitudinal axis 124. However, various other configurations and arrangements are contemplated for the gas supply lines 112i, 112 ₂ . In particular, the number and the arrangement of the gas injection port(s) 148 can be varied to suit the needs of a particular application.

[0082] The gas supply unit 104 further includes first and second valve insulators 118i, 118 ₂ respectively disposed along the first and second gas supply lines 112i, 112 ₂ , downstream of the first and second gas supply valves 116i, 116 ₂ but outside of the vacuum chamber 140. The first and second valve insulators 118i, 118 ₂ are configured to provide electrical insulation of the first and second gas supply valves 116i, 116 ₂ , respectively, from the plasma source 102. In the illustrated embodiment, each of the valve insulators 118i, 118 ₂ is embodied by an electrically insulating conduit segment that extends between a first portion 154i and a second portion 156i of the respective gas supply line 112i, 112 ₂ . Each first portion 154i, 154 ₂ is embodied by a gas conduit (e.g., an electrically conducting pipe or tube) having an upstream end coupled to the respective gas supply valve 116i, 116 ₂ and a downstream end coupled to an upstream end of the respective valve insulator 118i, 118 ₂ . Each second portion 156i, 156 ₂ is embodied by another gas conduit (e.g., an electrically conducting pipe or tube) having an upstream end coupled to an downstream end of the respective valve insulator 118i, 118 ₂ and a downstream end terminating at the respective gas injection ports 148i, 148 ₂ formed through the outer electrode 122 and leading to the plasma chamber 106.

[0083] As in the embodiment of Fig. 2, the valve insulators 118i, 118 ₂ may each be made of any suitable electrically insulating material including, but not limited to, glass, ceramic, and glass-ceramic materials. It is appreciated that the first and second valve insulators 118i, 118 ₂ , which may or may not be identical to each other, may be of varying sizes, shapes, compositions, locations, and configurations depending on the application. Furthermore, although each one of the gas supply valves 116i, 116 ₂ of the gas supply unit 104 depicted in Fig. 3 includes a single valve insulator 118i, 118 ₂ , other embodiments may include multiple valve insulators disposed along each of the gas supply lines 112i, 112 ₂ to provide electrical insulation between the respective gas supply valve 116i, 116 ₂ and the plasma source 102. As in the embodiment of Fig. 2, the provision of the valve insulators 118i, 118 ₂ can ensure or help ensure the integrity and performance characteristics of the gas supply valves 116i, 116 ₂ during operation of the plasma generation system 100, by preventing or reducing the likelihood of dielectric breakdown or other electrical failure (e.g., spurious valve opening caused by noise) from occurring at the gas supply valves 116i, 116 ₂ .

[0084] Referring to Fig. 4, there is illustrated another embodiment of a plasma generation system 100. The embodiment of Fig. 4 shares several features with the embodiments of Figs. 2 and 3, which will not be described in detail again other than to highlight differences between them. The plasma generation system 100 of Fig. 4 generally includes a plasma source 102 and a gas supply unit 104. The plasma source 102 includes a plasma chamber 106, and the gas supply unit 104 is configured to supply a process gas 108 into the plasma chamber 106 to be energized into a plasma 110. The process gas 108 may be any suitable gas or gas mixture capable of being energized into the plasma 110. In some embodiments, the process gas 108 may include fusion reactants. The gas supply unit 104 includes a gas supply line 112 connecting the plasma chamber 106 to a gas source 114 configured to store the process gas 108, a gas supply valve 116 disposed along the gas supply line 112 and configured to control a flow of the process gas 108 injected into the plasma chamber 106, and a valve insulator 118 disposed and configured to provide electrical insulation of the gas supply valve 116 from the plasma source 102. The plasma source 102 includes an inner electrode 120 and an outer electrode 122 coaxially disposed around the inner electrode 120 with respect to a longitudinal axis 124 of the plasma source 102 to enclose at least part of the plasma chamber 106. The plasma source 102 also includes a plasma power supply 136 configured to couple energy into the plasma chamber 106 to energize the process gas 108 into the plasma 110. In the illustrated embodiment, the inner electrode 120 is electrically biased and the outer electrode 122 is electrically grounded, although different configurations may be used in other embodiments. The plasma source 102 further includes an electrode insulator 134 disposed and configured to provide electrical insulation between the inner electrode 120 and the outer electrode 122. The plasma generation system 100 further includes a vacuum system 138 that includes a vacuum chamber 140 that houses at least partially various components of the plasma source 102, including the inner electrode 120, the outer electrode 122, and the plasma chamber 106.

[0085] In the embodiment of Fig. 4, the gas supply valve 116 is embodied by a solenoid valve, and both the gas supply valve 116 and the valve insulator 118 are located inside the inner electrode 120. The valve insulator 118 is disposed along the gas supply line 112, downstream of the supply valve 116. The valve insulator 118 is configured to provide electrical insulation of the gas supply valve 116 from the plasma source 102, including from the electrically biased inner electrode 120. In the illustrated embodiment, the valve insulator 118 is embodied by an electrically insulating conduit segment that extends between a first portion 154 and a second portion 156 of the gas supply line 112. The first portion 154 is embodied by a gas conduit (e.g., an electrically conducting pipe or tube) having an upstream end coupled to the gas supply valve 116 and a downstream end coupled to the valve insulator 118. The second portion 156 is embodied by another gas conduit (e.g., an electrically conducting pipe or tube) having an upstream end coupled to the valve insulator 118 and a downstream end terminating at a gas injection port 148 formed through the front end 126 of the inner electrode 120 and leading to the plasma chamber 106. In other embodiments, the gas injection port 148 may be formed through the circumferential wall of the inner electrode. It is appreciated that the gas injection port configuration illustrated in Fig. 4 is provided by way of example only, and that the number and the arrangement of the gas injection port(s) 148 can be varied to suit the needs of a particular application.

[0086] The valve insulator 118 can be made of any suitable electrically insulating material including, but not limited to, glass, ceramic, and glass-ceramic materials. Furthermore, although the gas supply unit 104 depicted in Fig. 4 includes a single valve insulator 118, other embodiments may include multiple valve insulators disposed along the gas supply line 112 between the gas supply valve 116 and the gas injection port 148.

[0087] As in the embodiment of Figs. 2 and 3, the provision of the valve insulator 118 can ensure or help ensure the integrity and performance characteristics of the gas supply valve 116 by preventing or reducing the likelihood of dielectric breakdown or other electrical failure. For example, in the embodiment of Fig. 4, the inner electrode 120 is electrically biased, generally to relatively high voltages (e.g., larger than a few kV), while the outer electrode 122 and the vacuum chamber 140 are electrically grounded. Since the portions 154, 156 of the gas supply line 112 downstream of the gas supply valve 116 extend within and pass through the electrically biased inner electrode 120, there are risks in the absence of the valve insulator 118 that high voltages be induced between the inner electrode 120 and the gas supply valve 116 and cause unwanted consequences on the structural integrity and operation of the gas supply valve 116. As noted above with respect to the embodiment illustrated in Fig. 2, the provision of the valve insulator 118 along the gas supply line 112 can eliminate or at least reduce such consequences.

[0088] Referring generally to Figs. 2 to 4, it is appreciated that the embodiments of the plasma generation system 100 disclosed herein may also include a control and processing device 158 configured for controlling, monitoring, and/or coordinating the functions and operations of various components of the plasma generation system 100 as well as various temperature, pressure, flow rate, and power conditions. Non-limiting examples of components that can be controlled by the control and processing device 158 include the plasma power supply 136 of the plasma source 102, the gas supply valve 116 of the gas supply unit 104, and the pressure control unit 146 of the vacuum system 138. For example, the control and processing device 158 may be configured to control the operation of the gas supply unit 104 to supply the process gas 108 to the plasma chamber 106 of the plasma source 102, including by controlling the operation of the gas supply valve to control the flow of the process gas 108 along the gas supply line 112 and into the plasma chamber 106; to control the operation of the plasma power supply 136 to supply power to the plasma chamber 106 to energize the process gas 108 into the plasma 110; and to control the operation of the pressure control unit 146 to control the pressure inside the vacuum chamber 140. The control and processing device 158 may be implemented in hardware, software, firmware, or any combination thereof, and be connected to various components of the plasma generation system 100 via wired and/or wireless communication links configured to send and/or receive various types of signals, such as timing and control signals, measurement signals, and data signals. The control and processing device 158 may be controlled by direct user input and/or by programmed instructions, and may include an operating system for controlling and managing various functions of the plasma generation system 100. Depending on the application, the control and processing device 158 may be fully or partly integrated with, or physically separate from, the other hardware components of the plasma generation system 100. The control and processing device 158 can include a processor 160 and a memory 162.

[0089] The processor 160 may be able to execute computer programs, also generally known as commands, instructions, functions, processes, software codes, executables, applications, and the like. It should be noted that although the processor 160 in Figs. 2 to 4 is depicted as a single entity for illustrative purposes, the term “processor” should not be construed as being limited to a single processor, and accordingly, any known processor architecture may be used. In some implementations, the processor 160 may include a plurality of processing units. Such processing units may be physically located within the same device, or the processor 160 may represent processing functionality of a plurality of devices operating in coordination. For example, the processor 160 may include or be part of a computer; a microprocessor; a microcontroller; a coprocessor; a central processing unit (CPU); an image signal processor (ISP); a digital signal processor (DSP) running on a system on a chip (SoC); a single-board computer (SBC); a dedicated graphics processing unit (GPU); a special-purpose programmable logic device embodied in hardware device, such as, for example, a field-programmable gate array (FPGA) or an application-specific integrated circuit (ASIC); and/or other mechanisms configured to electronically process information and to operate collectively as a processor.

[0090] The memory 162, which may also be referred to as a “computer readable storage medium” is capable of storing computer programs and other data to be retrieved by the processor 160. In the present description, the terms “computer readable storage medium” and “computer readable memory” are intended to refer to a non-transitory and tangible computer product that can store and communicate executable instructions for the implementation of various steps of the methods disclosed herein. The computer readable memory may be any computer data storage device or assembly of such devices, including a random-access memory (RAM) device; a dynamic RAM device; a read-only memory (ROM) device; a magnetic storage device, such as a hard disk drive; an optical storage device, such as an optical disc drive; a solid-state storage device, such as a solid-state drive and a flash memory drive; and/or any other non-transitory memory technologies. A plurality of such storage devices may be provided. The computer readable memory may be associated with, coupled to, or included in a computer or processor configured to execute instructions contained in a computer program stored in the computer readable memory and relating to various functions associated with the computer.

[0091] The plasma generation system 100 may also include one or more user interface devices (not shown) operatively connected to the control and processing device 158 to allow the input of commands and queries to the plasma generation system 100, as well as present the outcomes of the commands and queries. The user interface devices may include input devices (e.g., a touch screen, a keypad, a keyboard, a mouse, a switch, and the like) and output devices (e.g., a display screen, a printer, visual and audible indicators and alerts, and the like).

[0092] Numerous modifications could be made to the embodiments described above without departing from the scope of the appended claims.