Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21B—FUSION REACTORS
  • G21B3/00—Low temperature nuclear fusion reactors, e.g. alleged cold fusion reactors
  • G21B3/006—Fusion by impact, e.g. cluster/beam interaction, ion beam collisions, impact on a target
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21B—FUSION REACTORS
  • G21B1/00—Thermonuclear fusion reactors
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21B—FUSION REACTORS
  • G21B1/00—Thermonuclear fusion reactors
  • G21B1/05—Thermonuclear fusion reactors with magnetic or electric plasma confinement
  • G21B1/052—Thermonuclear fusion reactors with magnetic or electric plasma confinement reversed field configuration
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
  • H05H1/00—Generating plasma; Handling plasma
  • H05H1/02—Arrangements for confining plasma by electric or magnetic fields; Arrangements for heating plasma
  • H05H1/10—Arrangements for confining plasma by electric or magnetic fields; Arrangements for heating plasma using externally-applied magnetic fields only, e.g. Q-machines, Yin-Yang, base-ball
  • H05H1/12—Arrangements for confining plasma by electric or magnetic fields; Arrangements for heating plasma using externally-applied magnetic fields only, e.g. Q-machines, Yin-Yang, base-ball wherein the containment vessel forms a closed or nearly closed loop
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E30/00—Energy generation of nuclear origin
  • Y02E30/10—Nuclear fusion reactors

Definitions

• TITLE OF INVENTION Method and Apparatus for Compressing Plasma to a High Energy State
• the present invention relates generally to the field of plasma physics. More particularly, the invention concerns a method and apparatus for compressing plasma to a high energy state.
• MCF Magnetic Confinement
• ICF Laser Inertial Confinement
• ITER International Thermonuclear Experimental Reactor
• NEF National Ignition Facility
• ICF attempts to hold a high-density 10 m " plasma for nanoseconds.
• Magnetized Target Fusion mitigates the problems encountered at either extreme by sustaining a medium-density 10 24 m "3 plasma for only several milliseconds, while simultaneously reducing the minimum reactor size and cost as compared to MCF or ICF.
• the University of Washington Plasma Physics Laboratory has long advocated cleanliness requirements to avoid plasma impurities. They also utilize newer and more efficient methods to form and accelerate compact toroids.
• the pure research of the University is not focused on advanced plasma compression for MTF and the University has not attempted to translate a CT along a curved wall made of beryllium or lithium-silicon, which are much lower-Z materials than their walls (made of silicon dioxide).
• Prior art compact toroid compression mechanisms include, but are not limited to the following:
• Hydraulic hydro-forming wall
• Such mechanisms which require sub- microsecond-precision timing, require highly complex control systems.
• the liquid walls of such mechanisms add high-atomic-number contaminants to the plasma that significantly increase radiation loss rates from the plasma.
• the thrust of the present invention is to provide a compact toroid plasma structure compression assembly that is superior to and overcomes the problems associated with the various mechanisms described in the preceding paragraphs. More particularly, through analysis of the disadvantages of the aforementioned prior approaches, it has been possible to derive a unique set of design features that yield a novel approach with a distinct advantage. The details of these novel design features will be described further in the specification that follows. With the foregoing in mind, it is an object of the present invention to provide a compressor assembly of novel design within which a plasma can be efficiently compressed to a high energy state.
• a compressor assembly of the aforementioned character which includes an elongated spiral passageway within which a compact toroid (CT) plasma structure can be efficiently compressed to a high-energy state by compressing the CT using its own momentum against the wall of the spiral passageway in a manner to induce heating by conservation of energy.
• CT compact toroid
• Another object of the invention is to provide a compressor assembly of the character described in the preceding paragraph, which includes a burn chamber that is in communication with the spiral passageway and into which the compressed CT is introduced following its compression.
• Another object of the invention is to provide a burn chamber of the character described in the preceding paragraph, in which a magnetic sensor is embedded in the burn chamber for measuring the magnetic field vector versus time.
• Another object of the invention is to provide a compressor assembly of the character described in the preceding paragraph, in which the burn chamber comprises a toroidal ring of constant cross-section, having at least one entrance port for receiving the compressed CT and having a multiplicity of smaller exhaust ports.
• Another object of the invention is to provide a method for compressing a CT to a high-energy state using a compressor having an elongated spiral passageway by injecting the CT into the spiral passageway in a manner to avoid ricochet of the CT along the walls of the passageway. More particularly, in accordance with the method of the invention, ricochet is avoided by ensuring that the bulk axial kinetic energy of the CT at the point of injection is greater than the design "target" thermal energy sought to be achieved at the end of compression.
• Another object of the invention is to provide a method of the character described in the preceding paragraph in which thermal conduction losses and particle diffusion losses are avoided by embedding a large magnetic field within the CT during formation, prior to launching the CT into the elongated spiral passageway.
• a highly magnetized CT impedes both thermal conduction losses and particle diffusion losses perpendicular to the embedded magnetic field lines.
• Another object of the invention is to provide a method of the character described in the preceding paragraphs, in which thermal conduction losses and particle diffusion losses are avoided by applying a plasma-impurity impeding coating to the walls of the elongated spiral passageway.
• these coatings include low atomic number materials, such as beryllium or lithium-silicon.
• Another object of the invention is to provide a method of the character described in the preceding paragraphs in which, following compression of the CT to the design "target" thermal energy, the CT is introduced into a burn chamber comprising a toroidal ring of constant cross-section having at least one entrance port for the compressed CT and having a multiplicity of smaller exhaust ports.
• Another object of the invention is to provide a method of the character described in which, following compression of the CT to the design "target" thermal energy, the CT is introduced into a burn chamber and after the burn is complete, the compressed CT is caused to dissipate into a neutral gas, which is pumped out of the burn chamber by means of a suitable vacuum pump.
• Figure 1 is a generally perspective view of one form of the apparatus of the invention for compressing plasma to a high energy state.
• Figure 2 is a generally perspective exploded view of one form of the plasma compressor of the apparatus showing the plasma structure to be compressed in position to be introduced into the plasma compressor.
• Figure 3 is a generally perspective exploded view of the plasma compressor illustrated in Figure 2.
• Figure 4 is a longitudinal, cross-sectional view of the plasma compressor.
• Figure 4A is a cross-sectional view taken along lines 4A-4A of Figure
• Figure 5 is a generally perspective exploded view of the burn chamber of the plasma compressor illustrating the plasma in its compressed state.
• Figure 6 is a generally perspective exploded view of an alternate form of the plasma compressor of the apparatus showing the plasma to be compressed in position to be introduced into the plasma compressor.
• Figure 7 is a generally perspective exploded view of the plasma compressor illustrated in Figure 6.
• Figure 8 is a longitudinal, cross-sectional view of the plasma compressor shown in Figure 6.
• Figure 9 is a generally perspective exploded view of the burn chamber of the plasma compressor of this latest form of the invention illustrating the plasma in its compressed state.
• Figure 10 is a list of loss equations for electrons.
• Figure 1 1 is a list of loss equations for ions.
• Figure 12 is a list of loss equations for particle transfer.
• the fusion rate can be appreciable if the temperature is at least of the order on 10 keV - corresponding roughly to 100 million degrees Kelvin.
• the rate of a fusion reaction is a function of the temperature, and it is characterized by a quantity called reactivity.
• the reactivity of a D-T reaction for example, has a broad peak between 30 keV and 100 keV.
• FIELD-REVERSED CONFIGURATION FRC
• An example of a compact toroid plasma structure is a Field-Reversed Configuration which is formed in a cylindrical coil which produces an axial magnetic field.
• the FRC belongs to the family of compact toroids. "Compact” implies the absence of internal material structures (e.g. magnet coils) allowing plasma to extend to the geometric axis. "Toroid” implies a topology of closed donut-shaped magnetic surfaces. The FRC is differentiated from other compact toroids by the absence of an appreciable toroidal magnetic field within the plasma.
• prime-mover subsystem means a system for converting fusion-generated ion and/or neutron thermal energy to electrical energy.
• the prime-mover subsystem may comprise a heat exchanger and may also comprise various types of selected direct-conversion subsystems of a character also well known by those skilled in the art.
• FIG. 20 one form of the apparatus of the invention for compressing plasma to a high energy state is there shown and generally designated by the numeral 20.
• This form of the apparatus comprises a compressor 22, a vacuum pump subsystem 24 connected to the compressor by an outlet port 25 and a wall-cleaning subsystem that is operably associated with the compressor.
• the wall- cleaning subsystem here comprises heater blankets 26a, such as those readily commercially available from BH Thermal Corporation of Columbus, Ohio and like sources, a glow discharge cleaning (GDC) system 26b such as a system that is readily commercially available from XEI Scientific, Inc. of Redwood City, California and an ion gettering pump 26c of the character readily available from commercial sources such as SAES Getters USA of Colorado Springs, Colorado.
• GDC glow discharge cleaning
• Apparatus 20 also includes a plasma source subsystem 28 that here comprises stator antenna coils with pre-ionization capability, such as those commercially available from sources such as Alpha Magnetics of Hayward, California, a gas pulse injection valve with fire control unit 30 of the character that is available from Parker Hannifin of Pine Brook, New Jersey, and a ejector coil subsystem 32 that is also available from Alpha Magnetics.
• the pre-ionization process is preferably powered by a radiofrequency generator of the character that can be obtained from T & C Power Conversion of Rochester, New York.
• Prime-mover subsystem which is generally designated in Figure 1 by the numeral 34, must be operably associated with a compressor 22 to convert the fusion-generated ion and/or neutron thermal energy to electrical energy.
• Prime-mover 34 here comprises a heat exchanger of a character well understood by those skilled in the art. Attached to the heat exchanger is a steam turbine, which is, in turn, attached to an electrical generator (not separately shown in the drawings).
• the prime- mover subsystem can also comprise various types of selected direct- conversion subsystems of a character also well known by those skilled in the art.
• the plasma compressor 22 comprises first and second sealably interconnected portions 36 and 38 that are constructed from a material selected from the group consisting of aluminum, steel, copper, silicon, magnesium, carbon-carbon composites, nickel super alloys, tungsten, or other refractory alloys (such as molybdenum, niobium or rhenium).
• portions 36 and 38 are formed using a conventional computer numerically controlled (CNC) machine, or a conventional electrical discharge machine (EDM), or by casting methods.
• CNC computer numerically controlled
• EDM electrical discharge machine
• each of the portions 36 and 38 is provided with an elongate spiral passageway 40 having continuous wall 40a.
• Each of the spiral passageways has an inlet 40b and an outlet 40c ( Figure 3). Disposed proximate the center of the compressor 22 and in communication with the outlet of the spiral passageway is the important burn chamber 41, the construction and operation of which will presently be described.
• inlet port component 42 is in communication with the inlet of the spiral passageway 43 ( Figure 4) that is formed when portions 36 and 38 are joined together in the manner illustrated in Figure 2 of the drawings by brazing, welding, diffusion bonding, or mechanical assembly (with bolts and seals).
• spiral passageway 43 is of progressively decreasing diameter with the smallest diameter of the passageway being in communication with the burn chamber 41.
• Both the inlet port component and the inner ring are also preferably formed from a material selected from the group consisting of aluminum, steel, copper, silicon, magnesium, carbon-carbon composites, tungsten, or other refractory alloys.
• the wall of the elongated spiral passageway 40 of the compressor 22, as well as all other internal surfaces of the compressor that are exposed to the plasma, must be provided with a coating "C" preferably comprising either lithium-silicon, beryllium, or diboride ceramic, all of which are electrically conductive and low atomic-number materials (see Figures 3 and 4A).
• a coating "C” preferably comprising either lithium-silicon, beryllium, or diboride ceramic, all of which are electrically conductive and low atomic-number materials (see Figures 3 and 4A).
• the lithium-silicon coating it is to be noted that because pure lithium metal reacts with water vapor in the air, it is necessary that it be strictly maintained under vacuum between the point of manufacture of the coating powder and its application to the internal walls of the compressor.
• an electrically-conductive diboride ceramic or similar composite coating that consists of low atomic-number elements, which sputter slowly, could also advantageously be used to coat the internal walls of the compressor.
• the various techniques for coating the interior walls of the compressor are well known to those skilled in the art. For beryllium coatings, these techniques are fully described in a work entitled Beryllium Chemistry and Processing, Kenneth A. Walsh, Edgar E. Vidal, et al, ASM International (2009) (see particularly, Chapter 22, "Beryllium Coating Processes", Alfred Goldberg, pp. 361 -399).
• the inlet port component 42, the inner ring 44 and the inner walls of the compressor 22 that are exposed to the plasma are carefully cleaned and the various components of the compressor are joined together in the manner well understood by those skilled in the art, such as by brazing, welding, diffusion bonding, or mechanical assembly.
• the compressor 22 is integrated with the other subsystems of the apparatus of the invention in the manner depicted in Figure 1 of the drawings.
• These subsystems include the previously described vacuum pump subsystem 24, the wall-cleaning subsystem that comprises heater blankets 26a, a glow discharge cleaning (GDC) system 26b and an ion gettering pump 26c and the plasma source subsystem 28.
• GDC glow discharge cleaning
• the prime-mover subsystem 34 is interconnected with the compressor 22 in the manner indicated in Figure 1 of the drawings.
• a variety of well-known diagnostic tools around the apparatus (not shown in the drawings), such as a high-speed x-ray camera for observing shots, along with a neutron diagnostic, plus Rogowski coils for timing the ejection speed of the CT through the input port, as well as the speed of the CT in the burn chamber 41.
• diagnostic tools such as a high-speed x-ray camera for observing shots, along with a neutron diagnostic, plus Rogowski coils for timing the ejection speed of the CT through the input port, as well as the speed of the CT in the burn chamber 41.
• FIG. 52 This alternate form of the compression unit is illustrated in Figures 6-9 of the drawings and is generally designated by the numeral 52.
• This embodiment is similar in many respects to the embodiment shown in Figures 1 through 5 and functions in a substantially identical manner.
• the compressor is constructed from an electrically conductive, metallic alloy having a low atomic number, such as a beryllium alloy.
• portions 54 and 56 of the compressor unit 52 are formed from a block of beryllium alloy using a conventional computer numerically controlled (CNC) machine, or a conventional electrical discharge machine (EDM), or by casting method.
• CNC computer numerically controlled
• EDM conventional electrical discharge machine
• each of the portions 54 and 56 is provided with an elongated spiral passageway 58 having continuous wall 58a.
• Each of the spiral passageways has an inlet 58b and an outlet 58c ( Figure 7).
• an inlet port component 60, outlet port component 61 and an inner ring 62 are also preferably formed from a low atomic number, electrically conductive material, such as a beryllium alloy.
• spiral passageway 58 is of progressively decreasing diameter with the smallest diameter of the passageway being in communication with the burn chamber 65.
• Disposed proximate the center of the compressor 52 and in communication with the outlet of the spiral passageway 63 is the important burn chamber 65 of this latest form of the invention, the construction and operation of which is substantially identical to the previously identified burn chamber 41.
• beryllium alloy material in constructing the compressor is somewhat less desirable than the use of the more common materials such as steel, copper, silicon, magnesium, tungsten or other refractory alloys, all of which absorb x-rays better than beryllium. Additionally, the use of these materials is considerably less hazardous and the materials combine the function of a vacuum structural wall and x-ray shielding wall into one component.
• gasses including but not limited to: hydrogen, deuterium, deuterium-tritium mixtures, pure tritium, helium-3, diborane and mixtures thereof can be used with the compression apparatus of the invention.
• the compression apparatus is used to compress a deuterium-rich gas to ignition and/or "burn" conditions, a portion of the burn ash will contain the rare gas helium-3. This is because the helium-3 generated from the reacted deuterium has a slower initial speed than other generated particles, such as tritium, and thus more easily thermalizes in the plasma.
• a filtration system attached to the vacuum pumps will need to separate the isotopes in the exhaust.
• This apparatus is used to collect and purify the helium-3, as well as other exhaust products (such as tritium) that should not be vented to atmosphere from the pump exhaust. Additionally, hydrogen- 1 (protons) and helium-4 could be obtained from the exhaust using an isotopic separating filtration system.
• the first step in carrying out the method of the present invention is to form a compact torus (CT) plasma structure.
• CT compact torus
• FRC Field Reversed Configuration
• An FRC is formed in a cylindrical coil which produces an axial magnetic field.
• an axial bias field is applied, then the gas is pre-ionized, which "freezes in” the bias field, and finally the axial field is reversed.
• the ends reconnection of the bias field and the main field occurs, producing closed field lines.
• the CT which is identified in the drawings by the numeral 68, is launched at high speed into the inlet port component 42 of the plasma compressor of the invention.
• the CT As will be discussed in greater detail in the paragraphs that follow, as the CT travels through the plasma compressor it is crushed against a low atomic number material wall of the elongated spiral by means of its own inertia, inducing heating by conservation of energy.
• the internal thermal energy of the CT increases as its kinetic energy decreases.
• the pressure force it exerts has a vector component in the opposite direction to its forward motion (unless the walls are of constant cross-section). Therefore, it is important that the bulk axial kinetic energy of the CT at the point of ejection be greater than the design "target" thermal energy at the end of compression, to avoid a ricochet effect along the walls.
• a highly magnetized CT impedes both thermal conduction losses and particle diffusion losses from its core to the walls.
• the compressed CT 68a Once compressed to the design "target" thermal energy, the compressed CT 68a enters a comparatively short transfer conduit 70, which guides it away from the plane of symmetry of the compressor, and into the burn chamber 41.
• the burn chamber comprises a toroidal ring of constant cross-section, with a single entrance port for the compressed CT 68a ( Figures 3 and 7), and multiple smaller exhaust ports 72 ( Figure 5) which are in communication with the vacuum system 24.
• the compressed CT 68a dissipates into neutral gas, which is pumped out through the main vacuum exit port 74.
• the inner ring is provided with a circular hole 78, which is adapted to receive an alignment gauge pin during assembly (not shown). After assembly, the alignment gauge pin is removed, leaving two through-holes that can be conveniently used for the insertion of diagnostic probes, such as a Rogowski coil loop.
• a major advantage of the method of the present invention is that neutral beams are not necessary for heating the plasma, maintaining the compact toroid plasma thermal energy, or providing stability to the plasma structure. Another advantage of the method is that collapsible walls are not needed for compressing the plasma. Additionally, in practice, the compression apparatus of the invention can be used multiple times.
• the reaction cycle consists of the following five equations:
• These features will minimize losses due to impurities entering the plasma from the walls.
• Bremsstrahlung radiation is strongly affected by the average ion charge Z of the plasma, as the multi-pole non-relativistic equation A.2 ( Figure 10) indicates.
• Bremsstrahlung occurs in the x-ray spectrum and leaves the plasma.
• Bremsstrahlung is dominant only at high energy levels that are commensurate with burn conditions. For this reason, and the fact that the plasma is transparent to x-rays, Bremsstrahlung is usually the primary loss mechanism considered in simulation programs.
• recombination and excitation line radiation dominate the plasma's radiative loss mechanisms. This is especially the case for high-impurity content plasma.
• Recombination radiation governed by equation A.3 ( Figure 10) is the loss most strongly affected by Z. As can be seen inside the integrand, recombination radiation is extremely sensitive to increases in Z. It can be orders of magnitude less than Bremsstrahlung for a pure hydrogenic plasma, but can rapidly exceed Bremsstrahlung at lower energy levels from even moderate impurity content. Thus, by controlling impurities, the recombination radiation loss mechanism can be minimized Similarly, excitation line radiation in equation A.4 ( Figure 10) is affected by Z. Although not as apparent from this top-level equation, the calculation of N a utilizes a nonlinear function with Z as a directly dependant variable.
• Recombination and line radiation are often over-looked in sizing calculations, as they are assumed to be negligible as compared to Bremsstrahlung. This is the case under certain circumstances, but it is important to include their equations in case impurities enter the plasma. Overall, it is always beneficial (loss-reducing) to minimize the average Z. This is best accomplished by keeping impurities out of the plasma by utilizing clean, low-Z walls that sputter at as low a rate as possible.
• simulating sputtering of impurities from the wall (equation A.16 - Figure 12) and tracking magnetic dissipation (equation A.7 - Figure 10) allow estimation of how many impurities a wall will impart to a transient plasma and how long its internal magnetic field will last, respectively.
• the remaining effects of ion-to-electron kinetic transfer collisions (equation A.12 - Figure 1 1), product energy ion apportionment (equation A.13 - Figure 1 1), product energy ion thermalization (equation A.14 - Figure 12), and particle thermalization (equation A.17 - Figure 11) are essential to accounting for the allotment of energy and particles coming from core burn dynamics. In effect, they determine not the burn rate, but rather how to apportion the fusion energy coming from the original gain equation A.1 , given the state of the plasma as instigated by an external device.
• a convenient diameter for the starting and ending CT is 137 and 19 millimeters, respectively.
• the initial embedded magnetic field is preferably on the order of 6 ⁇ 1 Tesla and the minimum initial plasma ion density is approximately 5xl0 15 particles per cubic centimeter.
• the ejection speed of the CT requires a minimum of 4.8x10 6 meters per second and the minimum amount of time required for compression is on the order of 2 microseconds.

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• 2011
  • 2011-11-09 JP JP2014541010A patent/JP2015501918A/ja active Pending
  • 2011-11-09 CN CN201180074770.5A patent/CN104067349A/zh active Pending
  • 2011-11-09 EP EP11875462.1A patent/EP2777047A4/de not_active Withdrawn
  • 2011-11-09 WO PCT/US2011/001879 patent/WO2013070179A1/en active Application Filing
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