HIGH EFFICIENCY PLASMA CREATION SYSTEM AND METHOD

Abstract

A chamber cross-sectional multi-stage plasma arrangement characterized by escalating charge movement towards chamber center axis through one or more escalation stages contributing to the heating of the plasma, the centering of the plasma on the chamber axis, and creating rotation of the plasma therein. Rotation of the plasma around its axis induces a self-generated magnetic field, which in turn increases plasma stability and confinement. Some of the said stages of the multi-stage arrangement may be created by physical elements and components while others may be induced or generated by externally applying magnetic and/or electric fields or their combinations and/or by injection of electrons, ions or other plasma.

Claims

1. A stable plasma obtainment and confinement system, comprising: a. a cylindrical chamber having a substantially reduced internal pressure, typically 10-3-10-7 Torr, and having a central axis and a first and a second distal ends; b. a working gas source coupled with a means for injecting gas into the cylindrical chamber; c. a means for generating a magnetic field in the cylindrical chamber; d. a means for generating a plasma in the cylindrical chamber; e. at least one physical anode wherein at least one of the at least one physical anode is configured around the central axis and proximal to a first distal end; f. at least one physical cathode wherein at least one of the at least one physical cathode is configured coaxially with the cylindrical chamber and proximal to a second distal end; g. at least one immersed electrode having a tip and being immersed within a volume defined by the cylindrical chamber and configured coaxially therewith; and h. a controlling unit connected to other system components; wherein escalation of charge movement towards chamber center axis substantially contributes to ion heating in chamber and to rotation of a main portion of the plasma therein, bringing about a self-generated local magnetic field, thereby increasing main plasma stability and confinement, and wherein at least one volume of plasma not contained in the main plasma accumulates around the tip of the at least one immersed electrode, and wherein the rotation of said at least one volume of plasma not contained in the main plasma brings about a self-generated local electric/magnetic field that produces an ion mirroring effect (ion deflection).

2. The system of claim 1, further comprising one or more virtual escalation stages created by induction or generation of electric or magnetic/electric fields on regions of plasma within the cylindrical chamber, said regions being arranged concentrically around the axis of the cylindrical chamber.

3. The system of claim 2, wherein said one or more virtual escalation stages produce an outer ionization stage (OIS) region of the plasma within the cylindrical chamber distinct from a main reaction stage (MRS), wherein the MRS is arranged concentrically within the OIS, and wherein self-inducement and self-generation of electric/magnetic fields in the OIS further increases the main plasma stability and confinement in the MRS.

4. The system of claim 3, wherein said one or more virtual escalation stages contribute to the accumulation of the volume of plasma around the tip of the at least one immersed electrode.

5. The system of claim 1, further comprising one or more physical escalation stages arranged concentrically around the axis of the cylindrical chamber.

6. The system of claim 5, wherein said one or more physical escalation stages produce an outer ionization stage (OIS) region of the plasma within the cylindrical chamber distinct from a main reaction stage (MRS), wherein the MRS is arranged concentrically within the OIS, and wherein self-inducement and self-generation of electric/magnetic fields in the OIS further increases the main plasma stability and confinement in the MRS.

7. The system of claim 6, wherein said one or more physical escalation stages contribute to the accumulation of the volume of plasma around the tip of the at least one immersed electrode.

8. The system of claim 1, further comprising: one or more virtual escalation stages created by induction or generation of electric or magnetic/electric fields on regions of plasma within the cylindrical chamber, said regions being arranged concentrically around the axis of the cylindrical chamber; and one or more physical escalation stages arranged concentrically around the axis of the cylindrical chamber; wherein one or both of said one or more virtual escalation stage or said one or more physical escalation stages produce an outer ionization stage (OIS) region of the plasma within the cylindrical chamber distinct from a main reaction stage (MRS), wherein the MRS is arranged concentrically within the OIS, and wherein self-inducement and self-generation of electric/magnetic fields in the OIS further increases the main plasma stability and confinement in the MRS.

9. The system of claim 1, further comprising: one or more virtual escalation stages created by induction or generation of electric or magnetic/electric fields on regions of plasma within the cylindrical chamber, said regions being arranged concentrically around the axis of the cylindrical chamber; and one or more physical escalation stages arranged concentrically around the axis of the cylindrical chamber; wherein one or both of said one or more virtual escalation stage or said one or more physical escalation stages contribute to the accumulation of the volume of plasma around the tip of the at least one immersed electrode.

10. The system of claim 1, wherein at least one at least one immersed electrode is configured as a physical cathode.

11. The system of claim 1, wherein the at least one immersed electrode is two immersed electrodes disposed at both distal ends of the cylindrical chamber.

12. The system of claim 11, wherein the main plasma is trapped between two ion mirrors produced by two regions of plasma accumulated around the tips of said two immersed electrodes.

13. The system of claim 1, further comprising at least one power source for providing power to at least one of: means of generating a magnetic field; the at least one physical cathode; the at least one physical anode; the at least one immersed electrode, wherein operation of the at least one power source is coordinated by the controlling unit.

14. The system of claim 13, wherein the at least one power source provides power in form of a pulse.

15. The system of claim 13, wherein the at least one power source providing power in form of a pulse provides said pulse to the means of generating a magnetic field, thereby producing a magnetic field of at least 3 Tesla.

16. The system of claim 14, wherein the at least one power source is at least one capacitor bank.

17. The system of claim 1, wherein the tip of at least one of the at least one immersed electrode is disposed to produce thermionic emission.

18. The system of claim 17, wherein the thermionic emission produced by the tip of the at least one of the at least one the immersed electrode is the means of producing a plasma in the cylindrical chamber.

19. The system of claim 1, wherein the tip of the at least one of the at least one immersed electrode is composed partially or entirely of a high temperature resistant material, for example Tungsten or Molybdenum.

20. The system of claim 1, wherein the tip of the at least one of the at least one immersed electrode is characterized geometrically as having varying radii.

21. The system of claim 1, wherein the tip of the at least one of the at least one immersed electrode is characterized geometrically as having multiple planes.

22. A method for stably obtaining and confining a plasma, comprising: a. reducing internal pressure of cylindrical chamber, typically to between 10-3-10-7 Torr., said cylindrical chamber having a central axis and a first and a second distal end; b. injecting a working gas from a working gas source into the cylindrical chamber; c. generating a magnetic field in the cylindrical chamber; d. generating a plasma in the cylindrical chamber; e. disposing at least one physical anode around the central axis and proximal to a first distal end; f. disposing at least one physical cathode coaxially with the cylindrical chamber and proximal to a second distal end; g. disposing at least one immersed electrode having a tip and being immersed within a volume defined by the cylindrical chamber and configured coaxially therewith; and h. controlling system components with a controlling unit, whereby escalation of charge movement towards chamber center axis substantially contributes to ion heating in chamber and to rotation of a main plasma therein, bringing about a self-generated local magnetic field, thereby increasing main plasma stability and confinement, and whereby at least one volume of plasma not contained in the main plasma accumulates around the tip of the at least one immersed electrode, and wherein the rotation of said at least one volume of plasma not contained in the main plasma brings about a self-generated local electric/magnetic field that produces an ion mirror having an ion mirroring effect (ion deflection).

Description

BRIEF DESCRIPTION OF THE FIGURES

[0025] Some embodiments of the invention are described herein with reference to the accompanying figures. The description, together with the figures, makes apparent to a person having ordinary skill in the art how some embodiments may be practiced. The figures are for the purpose of illustrative description and no attempt is made to show details of an embodiment in more detail than is necessary for a fundamental understanding of the invention.

[0026] In the Figures:

[0027] FIG. 1 constitutes a schematic view of the high efficiency plasma system, according to some embodiments of the invention.

[0028] FIG. 2A-2B constitute schematic views of the high efficiency plasma system chamber, according to some embodiments of the invention.

[0029] FIG. 3A-3B constitute schematic views of the ionization stages in the high efficiency plasma system chamber reaction area, according to some embodiments of the invention.

[0030] FIG. 4A depicts axial section of Particle-In-Cell simulation results of ion acceleration in the high efficiency plasma system chamber reaction area, according to some embodiments of the invention.

[0031] FIG. 4B depicts axial section of Particle-In-Cell simulation results of electron acceleration in the high efficiency plasma system chamber reaction area, according to some embodiments of the invention.

[0032] FIG. 4C depicts cross section of Particle-In-Cell simulation results of ion radial direction velocity in the high efficiency plasma system chamber reaction area, according to some embodiments of the invention.

[0033] FIG. 4D depicts cross section of Particle-In-Cell simulation results of ion phi direction velocity in the high efficiency plasma system chamber reaction area, according to some embodiments of the invention.

[0034] FIG. 5A-5B constitute schematic examples of magnetic and electric fields obtainable upon operation of the high efficiency plasma system and method, according to some embodiment of the invention.

[0035] FIG. 6A is a photographic image of a test apparatus according to some embodiment of the invention showing the high efficiency plasma system chamber reaction area looking along the chamber's axis line, demonstrating plasma circulation in a lower magnetic field.

[0036] FIG. 6B is a photographic image of a test apparatus according to some embodiment of the invention showing the high efficiency plasma system chamber reaction area looking along the chamber's axis line, demonstrating plasma circulation in a higher magnetic field.

[0037] FIG. 7 is a chart of voltage measured in probes used in a test apparatus according to some embodiment of the invention versus externally applied voltage values.

[0038] FIG. 8A-8G show examples of electrode design according to some embodiments of the invention.

[0039] FIG. 9 constitutes a schematic example of obtainment of ion mirroring obtainable upon operation of the high efficiency plasma system and method, according to some embodiment of the invention.

[0040] FIG. 10A-10D show examples of mesh cylinder design according to some embodiments of the invention.

DETAILED DESCRIPTION OF SOME EMBODIMENTS AND EXAMPLES

[0041] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, and components, modules, units and/or circuits have not been described in detail so as not to obscure the invention. Some features or elements described with respect to one embodiment may be combined with features or elements described with respect to other embodiments. For the sake of clarity, discussion of same or similar features or elements may not be repeated.

[0042] Although embodiments of the invention are not limited in this regard, discussions utilizing terms such as, for example, controlling processing, computing, calculating, determining, establishing, analyzing, checking, setting, receiving, or the like, may refer to operation(s) and/or process(es) of a controller, a computer, a computing platform, a computing system, or other electronic computing device, that manipulates and/or transforms data represented as physical (e.g., electronic) quantities within the computer's registers and/or memories into other data similarly represented as physical quantities within the computer's registers and/or memories or other information non-transitory storage medium that may store instructions to perform operations and/or processes.

[0043] The term controller, as used herein, refers to any type of computing platform or component that may be provisioned with a Central Processing Unit (CPU) or microprocessors, and may be provisioned with several input/output (I/O) ports, for example, a general-purpose computer such as a personal computer, laptop, tablet, mobile cellular phone, controller chip, SoC or a cloud computing system.

[0044] Unless explicitly stated, the method embodiments described herein are not constrained to a particular order or sequence. Additionally, some of the described method embodiments or elements thereof can occur or be performed simultaneously, at the same point in time, or concurrently.

[0045] According to one aspect of the invention, an axial-symmetric shape of the plasma is maintained stable and coaxial by a combination of part or all of the following discussed system components or elements, as schematically exemplified in FIG. 1, substantially consisting of [0046] (i) a cylindrical chamber (100) having substantially reduced internal pressure; [0047] (ii) inner anode element (145) [0048] (iii) an electrode (140) positioned at each end of tubular chamber connected to external power supply; [0049] (iv) external solenoids or magnets or combination thereof (160); [0050] (v) capacitor banks (for e/m pulse) external to chamber (800); [0051] (vi) controlling unit (500); [0052] (vii) very high quality vacuum (characteristically of 10-3-10-7 Torr) pumping system (600); [0053] (viii) pre-heating electric power supply (700). [0054] (ix) working gas source (900) coupled with a control valve (920) connected to a gas inlet (910).

[0055] Reference is made to FIG. 2A whereby tubular chamber (100) is optionally combined with an inner anode element (145) (proximal to the chamber's internal skin), as initial outer stage to inner cascaded stages of external and inner generated or induced magnetic and electrical fields. While making reference to FIG. 2B wherein optional electrodes (140) at ends of tubular chamber act as cathodes in ionization process.

[0056] Whereas in one embodiment, at least one inner tubular electric field is created by a conductive apparatus (135) or by virtual induced plasma (130) concentrically arranged on tubular chamber axis, wherein such inner field acts as a cascaded stage manipulating the ionization. Making reference to FIG. 3A showing the facilitation of Outer Ionization Stage (OIS) (300) which contributes to a high rate of ionization of the working gas originating from working gas source (900) controllably injected into chamber (100) through control valve (920) via gas inlet (910). This ionization is due to the relatively high electric field (typically 2-7 kV but also much larger ranges such as 2-20 kV or even larger) in outer cascade. The coupling of such ionization with rotation of the electrons about the chamber axis (110) due to the externally applied electric field (from pre-heating power supply (700)) and magnetic field (through magnetic coil or solenoids (160) coupled with capacitor bank (800)) contributes to the heating of the ions in the OIS (300) and their acceleration towards the chamber axis (110). Such acceleration which in itself contributes to gradient of a magnetic field leads to a compression of ions at and about chamber axis (110) and thereby contributing to the creation of stable plasma (130) at reaction area (170), in accordance with controller unit (500) directions. Making reference to FIG. 3B showing the facilitation of one embodiment, wherein at least two additional inner tubular electric fields are created by conductive apparatus (135) or by virtual plasma inducement concentrically arranged on tubular chamber axis (110), such inner fields act as additional cascaded stages manipulating the ionization through Outer Ionization Stage (OIS) (300) and Main Reaction Stage (MRS) (200). The upper parts of the cascaded stages, the OIS, contribute to a high rate of ionization of the working gas. This ionization is due to the relatively high electric field (typically 2-7 kV but also much larger ranges such as 2-20 kV or even larger) generated in outer cascade. Electric field at inner cascade stage, at the MRS, is to be of much larger magnitude (typically 10-35 kV but also much larger ranges such as 10-100 kV or even larger).

[0057] Such arrangements ensue electrons emitted from said optional electrodes (140) at ends of tubular chamber to create a virtual cathode (130) at axis of tubular chamber affected by externally applied magnetic and electrical fields coupled with the internally generated magnetic and electrical fields, bringing about magnetic and electrical forces on gas ions, in accordance with controller directions. As is demonstrated to be obtainable in FIG. 4A through FIG. 4D depicting certain Particle-In-Cell (PIC) simulation results conducted according to some embodiments of the invention. It being understood by those skilled in the art that PIC simulations are acceptable investigation and demonstration for plasma simulation techniques. FIG. 4A shows PIC simulation results of ion acceleration in the chamber (100) radial direction while FIG. 4B shows the confining of electrons to two stages of potential well: at area (401) proximal to chamber wall; and at area (402) of chamber axis (110). FIG. 4A and FIG. 4B exemplify the phenomena that ions are less affected by the magnetic field proportionate to their mass which is much heavier than that of the electrons. Thereby the said arrangement would facilitate the movement of ions between areas (401) and (402) as shown in FIG. 4A, while electrons substantially remain situated either in areas (401) or (402) as shown in FIG. 4B. Such PIC simulation demonstrates the facilitation of the OIS (300) and virtual cathode (130) at axis of tubular chamber creating the MRS (200). The ion movement characteristic ion (i) radial direction velocity is shown in FIG. 4C and ion (i) Phi direction (rotational) velocity in FIG. 4D, both shown against the stagnant electrons (c) in areas (401) and (402) accordingly. It would be appreciated by a person skilled in the art that such PIC simulations demonstrate the increased ion velocity, both radially as well as or alternatively rotationally, which is indicative of the high ion temperature obtainable at the chamber axis (110) area in the said arrangement.

[0058] According to some embodiments, a cylindrical chamber is used to encapsulate the process. The chamber walls may be made of various materials (varying from metals, ceramics, pyrex, glass and others). Different materials may have different advantages or disadvantages by way of strength, temperature conveyance, isolation, radiation transparency, opacity and other characteristics. According to some embodiments, chamber walls are conducive and may act as electrode (145) or as a stage in the cascade of magnetic and electrical fields.

[0059] According to some embodiments, cylindrical chamber (100) is initially highly depressurized to very high quality vacuum conditions (characteristically of 10-3-10-7 Torr) prior to gas injection through gas inlet (910) connected to a control valve (920) in order to prevent interference/contamination by undesired particles of residual gasses. According to some embodiments, cylindrical chamber is filled with a working gas (Xenon/Argon/hydrogen/deuterium/or other relevant gases or combinations thereof depending on the plasma process to be implemented) at a predefined pressure. Gas in the chamber is ionized and effectively manipulated by applied magnetic and electric fields arranged according to the invention.

[0060] According to some embodiments, the outer circumference of cylinder chamber (100) contains an active conducting component which acts as an anode allowing for the induction of a radial electric field of high voltage that ionizes the gas in the chamber. Referring to FIGS. 2A and 2B this component of the outer chamber (100) is the first stage of the multi-stage anode arrangement an example of which is shown in FIG. 2 which comprises several stages of plasma some of which may be physical and others may be virtually induced. According to some embodiments of the invention, referring to FIG. 3, such stages are radially arranged in relation to the chamber axis (110), each stage causing the acceleration of ions towards central axis in the area of which plasma (130) is concentrated.

[0061] It being appreciated by a person skilled in the art that ion acceleration may be obtained by various magnetic and electrical fields and their combinations, by way of an un-limiting example, making reference to FIG. 1, according to some embodiments, the reaction area (170) of the chamber circumference (100) is surrounded by a fairly medium to low power magnet or magnetic coil (160) (typically of a magnitude of 0.1-0.5 Tesla or larger such as 0.1-2 Tesla). According to some embodiments, such MRS is evident at the longitudinal center of chamber and, according to some other embodiments, active part (170) may extend to ends of tubular chamber (100) such as in area of electrodes (140). Substantially, such arrangement allows for the application of a current pulse in the coil which causes a magnetic pulse which in turn causes the plasma in the chamber to compress and heat to higher efficiency of plasma processes.

[0062] According to some embodiments, maintainability of the system is improved due to its relatively small size. Pulse operated system enjoy prolonged life span of materials which otherwise would deteriorate under continuous operationthus reducing MTBF and due replacements;

[0063] According to some embodiments, a multi-stage ionization is outlined in FIG. 3A showing the internal area in which the axi-distal edge of the cylindrical grid element or of the virtual mesh grid operate as the boundary and the cathode of the outer ionization stage (OIS) steps-up the plasma ionization level in the chamber which eventually increases the ion flux towards the axis of cylinder.

[0064] According to some embodiments, a multi-stage ionization is outlined in FIG. 3B showing the internal area in which the axi-distal edge of the cylindrical grid element or of the virtual mesh grid operate as the boundary and the cathode of the outer ionization stage (OIS) which steps-up the plasma ionization level in the chamber which eventually increases the ion flux towards the material cathode or virtual cathode passing through the Main Reaction Stage (MRS) at the axis of cylinder. According to some embodiments, as outlined in FIG. 3A, the creation of the MRS and the virtual cathode coincide thereby increasing the density of ions in the axis creating a higher probability of reaction between accelerated ions from the OIS stage with the ions in the combined MRS and virtual cathode volume. Ions passing under such conditions (per FIG. 3A or FIG. 3B) contribute to the creation of the designated plasma processes.

[0065] According to some embodiments, internal volume where plasma is concentrated, is surrounded by an internal metallic grid cylinder (135) (substantially lower than 15% mesh density and typically less than 5% mesh density). Metallic grid cylinder may be made of various materials (such as any conducting material that can withstand heat and has low absorption of water or other substances and will not contaminate the chamber, such as stainless steel, tungsten, molybdenum, and other materials) and be in various shapes and patterns (such as helical spring shape, perforated, slotted, whole, flute, etc. as some such examples as experimented are shown in FIG. 10A through 10D) (such internal cylindrical element is referred to hereinafter as mesh cylinder or cylindrical grid element).

[0066] According to some embodiments, instead of or in addition to the cylindrical grid element, an electromagnetic field may be locally generated producing a similar effect to that of a mesh cylinder (135) by manipulation of the multi-stage anode arrangement.

[0067] According to some embodiments, said cylindrical grid elements plays also the role of an anode for the MRS. The result being a cascade of stages the first of which is the external chamber's cylinder acting as an anode and the next being the cylindrical grid element anode. The next stage being a material cathode or a virtual cathode on axis of chamber cylinder in area of plasma, such cathodal character resulting from the application of the prior stages coupled with the electron emission electrodes at ends of active tubular chamber. The cross-product of the linear magnetic field flux in the chamber with a radial electric field within the chamber results in the creation of a strong internal magnetic field as schematically exemplified in FIG. 5A. This self-induced magnetic field (301) has closed field lines within the chamber. Such cross-product contributes to the contortion and coaxilization of the plasma without investment of substantially additional energy. Adjusting and optimizing the electric and magnetic fields and their cross-product creates strong confinement and thereby obtains high-pressure high-density highly-stable plasma (not un-similar to the conventional FRC effect). According to some embodiments, making reference to FIG. 5B, whereupon additionally an external magnetic pulse 302A (typically of magnitude 3-10 Tesla or larger) would increase the induced current, which is the product of the external magnetic field pulse (302A) and the external electric field, apparent in the chamber axis (110) thereby contorting the axial plasma contributing to an SSCP effect presenting a longitudinally concentrate of induced magnetic field (301A). Such effect is also evident in photographic images of a working test apparatus arranged according to the invention presented in FIG. 6A and FIG. 6B. FIG. 6A and FIG. 6B are photographic images of a system according to the invention showing the plasma circulating around the axis of the chamber under different external magnetic field application. Evidently, the plasma (300B) radius is larger under the stronger externally applied magnetic field and smaller radius (300A) under a lower externally applied magnetic field. A person skilled in the art would appreciate that the rotational energy is effectuated by the external radial electric field and its product with the external magnetic field (ExB) in the z direction (axial). Such change of the external magnetic field would characteristically dominantly contribute to the creation of the SSCP effect as visually demonstrated in the plasma contortion shown in FIG. 6A and FIG. 6B. Furthermore, a person skilled in the art would appreciate that applying a strong pulse of external magnetic field will create the effect substantially equivalent to a Pinch compressing and overcoming the centrifugal forces of the plasma thereby bringing about the heating of the plasma as well as increasing the plasma density in the MRS and bringing the plasma to highly energetic parameters. An example of obtaining such energetic parameters is show in FIG. 7 which presents a chart of voltage measured in probes versus externally applied voltage values as per test apparatus according to some embodiment of the invention. The test apparatus comprised of two Langmuir probes one of which located at bottom area of OIS and the other at the top of MRS area. The probes measured the plasma electric potential. FIG. 7 shows the high correlation between applying various heating/acceleration voltages to the measured plasma voltage which indicates the actual heating of the plasma at the MRS (200).

[0068] The acceleration of ions ensues an increase of temperature. This acceleration is a direct result of the static electric field which is considered to be an efficient method to provide kinetic energy to a charged particle. According to some embodiments, using the radial electric field creates an innate axisymmetric heating mechanism having a high degree of uniformity, which maintains the axial symmetry which is crucial for plasma stability.

[0069] A person skilled in the art would appreciate that plasma density may be increased by injecting additional gas into chamber. According to some embodiments, gas injection can be achieved through the cylinder wall (100) by gas inlet connected to a proportional valve (920). Controlling the injection of the gas through the chamber wall may further contribute to the effective distribution of the charged gas by way of influencing density disbursements in chamber volume.

[0070] According to some embodiments, electrodes (made of high temperature resistant materials, such as Tungsten/Molybdenum/or the like) are coaxially positioned at ends of tubular chamber and connected to high negative voltage. Such designs may be used to contribute to the electric field at the chamber axis and/or to facilitate as an electron emitting source. According to some embodiments, such electrodes can be either passive wherein heating is by the plasma itself from electrode tip (141) or active wherein the heating is externally induced in the electrode and thus actively causing emission of electrons from active electrode tip (141) (creating an electron gun).

[0071] According to some embodiments, said electrodes are characterized by a varying gradients and/or gradual changing radii and/or varying planes design comprising of several phases of different magnitude scale. Reference is made to FIG. 8A through 8G showing some such electrodes. According to some embodiments such electrodes as shown in FIGS. 8B and 8F may be characterized by three major areas of said phases: a relatively large magnitude phase (143); a mid-section phase tapering towards tip (142); and a tip section phase (141). According to other embodiments, additional alternate electrode designs are implementable (as may be shown in FIGS. 8A, 8C, 8D and 8E). Making reference to FIG. 8G showing yet another electrode design combined with an internal heating element (147) which when heated instigates high rate of electron emission from electrode tip (141).

[0072] Making reference to FIG. 9, an active electrode emits electrons from active tip (141). Such active emission is obtained by external heating element (700). The heat concentrated at the tip phase (141) causes the emission of electrons in a thermionic emission process. Thus, according to some embodiments of the invention, the emitted electrons are longitudinally forced by the electric field and held by the magnetic field towards the middle of the chamber thus contributing to the creation of an initial virtual cathode (130) and thereafter sustaining it at a substantially steady state.

[0073] According to some embodiments, the shape and structure of the electrodes immersed within the volume of the chamber creates an electron gun source. According to some embodiments, the shape and structure of the electrodes immersed within the volume of the chamber creates an electric mirror or electric deflector which is obtained by the said unique specific geometric shapes according to the invention such as per FIG. 8A through 8G. Whereas, a person skilled in the art would appreciate that such effects may be obtained by other specific multi-phased electrode designs in accordance with the invention.

[0074] By way of un-limiting example, reference is made to FIG. 9 which shows the electric field back mirror (171) created when placing coaxially immersed electrode (140) in chamber (100) aligned with its axis (110). In such example the plasma phase at its distal ends in area of electrode tip (141), placed at each end of chamber, accumulates a volume of ions. Making reference to FIG. 9 ion clouds (151), (152) and (153) which are not captured into the main plasma flux have a containment effect on the plasma shape and form in the chamber. Such clouds are considered to have a mirroring constraining effect whereby ions in trajectory towards ends of tubular chamber are contained by the electron cloud (as schematically shown in FIG. 9). According to some embodiments, such mirroring is obtained by the combination of the multi stage cascade arrangement in the chamber together with said multi-phased electrodes, without installing actual magnets at ends of linear design chamber to obtain a magnetic mirroring effect as may be suggested in other cylindrical designs. According to some embodiments, it is enough to rely on the electron emission from the plasma distal electrode phase. The axial location of the ion mirror will vary in accordance with many parameters, including the actual design of the phases of the electrode but in any case it is in a distance that creates the equilibrium between the ions and electrons that eventually establishes the ion mirror.

[0075] According to some embodiments, electron emitting electrodes are characterized by having at least two phases whereby phase arrangement is designed to induce ion and electron clouds in vicinity of electrode, whereby at least one phase is considerably larger in diameter in comparison with the other phase of the electrode.

[0076] According to some embodiments, electron emitting electrodes are characterized by having at least two phases whereby phase arrangement is designed to induce ion and electron clouds in vicinity of electrode, whereby through some of the phases electric current is driven and others are electro-statically charged.

[0077] According to some embodiments, electron emitting electrodes are arranged in a manner generating electric mirrors within chamber substantially reducing ion escape at ends of tubular chamber.

[0078] Operation of the currently contemplated system requires relatively small energy level input from external sources (compared to conventional systems) both for heating and for magnetic field build-up. A person skilled in the art would appreciate that implementing the unique design criteria derived from the approaches described hereinabove will present a highly efficient system.

[0079] Without limitation of any of hereinabove, a person skilled in the art would appreciate that the harvestable plasma obtainable in accordance with the suggested system and method may be used as a neutron source, as a source for extreme UV, in an etching process, energy harvesting and/or generally in or for high density high temperature plasma fusion processes.

[0080] Although the present invention has been described with reference to specific embodiments, this description is not meant to be construed in a limited sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the invention will become apparent to persons skilled in the art upon reference to the description of the invention. It is, therefore, contemplated that the appended claims will cover such modifications that fall within the scope of the invention.