EP1000527A1

EP1000527A1 - Method for generating energy by controlled plasma-induced nuclear fusion and device for the implementation of said method

Info

Publication number: EP1000527A1
Application number: EP98954158A
Authority: EP
Inventors: Jürgen ANDRÄ
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-09-20
Filing date: 1998-09-11
Publication date: 2000-05-17
Also published as: WO1999016291A1; AU1141699A; DE19741515A1

Abstract

The invention relates to a method for generating energy by controlled plasma-induced nuclear fusion and to a device for the implementation of the inventive method. Unlike suggested in large-scale fusion research, the inventive method provides for the ions to be heated selectively with ion cyclotron resonance by means of an electrical, resonant high frequency field impregnating the plasma in a large resonance volume containing at least 0.4 % of the total plasma volume. The intensity of the resonance magnetic field in the resonance volume remains constant, the differences being no greater or smaller than 1 %. The magnetic field strength from the resonance volume increases in all external directions. This enables efficient, selective ion heating whilst the electrons are cold. In contrast with existing and projected fusion plasma machines, ions with high kinetic energy in the spatial area of the minimum quantity of the magnetic field structure can be stored over a long period of time with little technical and economic expenditures and in relatively small volumes so that a stationary controllable fusion energy yield is achieved, whereby the heating of ions can be increased by inserting ions in the magnetic field structure.

Description

Process for energy generation with plasma-induced, controlled nuclear fusion and device for carrying out the process.

description

The invention relates to a method for generating energy with plasma-induced, controlled nuclear fusion according to the preamble of claim 1

Plasma-induced, controlled nuclear fusion is a technologically extremely complex, as yet unsolved problem (see Reference 1 U Schumacher, "Fusion Research", Scientific Book Society, Darmstadt, 1993, ISBN 3-534-10905-8). The general approach is to ignite a high-density plasma ( Density n> 10 ¹⁴ deuterons per cnr ³ ), which is heated to temperatures between 10 ⁶ and 10 ⁸ K in a fraction of a second and is then kept stable for as long as possible τ, today typically reaching seconds

The high temperatures are necessary in order to impart sufficient kinetic energy to deuterium nuclei so that they can fuse with tritium nuclei against Coulomb repulsion. Deuterium-tritium fusion has the largest fusion cross-section and is therefore used as a fusion fuel for future ones Fusion reactors favored

The resulting high-energy neutrons (14 MeV) are disadvantageous both for the energy balance and from the perspective of long-term radioactive side effects. The clean, neutron-free fusion could be achieved with the reaction p + ^π B - »3 x ⁴ He + 3 x 2 88 MeV which, at a significantly higher p-energy, has a smaller fusion cross-section than the deuterium-tritium reaction. Despite this problem, the proton-boron reaction should be carried out because of the favorable magnetic inclusion of protons, because of the favorable energy balance of its end products, and above all because of Missing radioactive side effects are taken into account. For all ions relevant for controlled nuclear fusion, such as positive hydrogen, deuterium, tritium, 1 IBor ions, etc., the term ions is used in the following

In order to keep the plasma stable, high magnetic fields (order of magnitude 1 to 10 T) are required, which should primarily prevent the plasma from spreading to the plasma chamber walls, because the plasma loses its energy when it comes into contact with a wall, ie it cools and creates contamination of the plasma with wall material, which also leads to energy loss of the plasma. In spite of optimized magnetic field constructions, such as in tokamaks or stellerators, the plasma-wall interactions cannot be avoided in principle To generate the high magnetic field, the transition today is from copper coil technology (e.g. Tokamak JET (Joint European Torus)) to superconducting coils, which are the more economical solution for long-term maintenance of the plasma (e.g. Stellerator Wendelstein VII X under construction, Tokamak ITER (International Thermonuclear Experimental Reactor) planned)

The energy losses of the plasma have to be compensated for by active heating of the plasma. To this end, the ohmic heating when the magnetic inclusion field is switched on and the HF-EZRH (high-frequency electron cyclotron resonance heating), which primarily use the electrons, have been used in tokamaks heating For direct ion heating, high-energy neutral particle injection and HF-IZRH (high-frequency ion cyclotron resonance heating) have been used so far, but the latter has not been optimized in previous fusion machines, ie the volume in which the magnetic field meets the IZR condition is a very small (<10 ^{~ 4} ) volume fraction of the total plasma volume. It also has the major disadvantage that it has to work at frequencies that are reflected by large-volume plasmas. It is therefore only effective in the edge zones of large-volume plasmas when using coupling antennas So far, the sum of all heating methods is not sufficient to reduce the plasma against all plasma generators Heating losses for the necessary periods of time to sufficient temperatures

The overall energy balance of these relationships leads to the technologically and economically very questionable result that only an enlargement of the plasma fusion machines designed so far can lead to a positive energy balance, i.e. that only gigantic machines have the prospect of producing more energy than consuming (e.g. the planned one ITER)

It is therefore the task to rethink the overall energy balance of fusion plasmas and to search for solutions that lead to energy-producing fusion reactors with less technological and economic effort and, above all, smaller dimensions

This object is achieved according to the invention in that a) the magnetic inclusion of the plasma is generated by permanent magnets or copper coil systems or superconducting magnetic coil systems with so-called MBM (minimum B magnetic field structures) (B is the magnitude of the magnetic field), several MBMs being arranged either in a straight line be or with an angular offset of 360 / N degrees and magnetic deflections of 360 / N degrees can be arranged so that N MBM result in a closed, N-square overall structure, b) the plasma heating permanently and very efficiently by RF wave absorption in the IZR (Ion Cyclotron Resonance) frequency is achieved in a resonance volume that is one Fills a fraction of at least 0 4% of the total plasma volume and selectively heats only the ions, whereby the penetration of the RF wave into the plasma either

(i) Electrode pairs of opposite, high-frequency alternating polarity comprising the plasma

(ii) or is achieved by a spatially structured, magnetic HF alternating field, which is superimposed on the MBM and which induces the local electrical HF IZR fields necessary for heating in the spatial IZR areas of the plasma

(iii) or by irradiation of two microwaves, the frequencies of which are above the plasma frequency and the difference frequency is equal to the respective ion cyclotron resonance frequency, the difference frequency in the plasma being generated via nonlinear plasma interactions, which are particularly effective in dense plasmas c) the ion heating is supported by the fact that in the opposite direction to the so-called escape directions for ions from the magnetic structure, positive or negative ions are injected into the magnetic structure with energies which correspond to the order of magnitude of the optimal fusion energy

With selective ion heating, the electron (energy) temperature remains low compared to previous fusion machines. A thermal imbalance can thus be achieved in favor of a high ion (energy) temperature compared to a relatively low electron (energy) temperature Reaching energies> 1 keV are considered to be bumpless in plasma densities up to 2 TO ¹⁴ cm ^{"3 of} the planned ITER, so that ion trajectory calculations under the influence of an electrical IZR- (ion cyclotron resonance) -HF- ( High-frequency) heating field provide a good description of the overall plasma. Such calculations applied to an electrical IZR-HF heating in an MBM result in a high ion energy density, which is localized in spatial proximity to the B minimum, and which can only be achieved by the ion cyclotron radius The radial spatial dimension of the plasma and the strength of the magnetic confinement is limited by the IZR-HF heating with electrical field components In the magnetic field lines, the ions primarily gain rotational energy around the magnetic field lines, so that the loss of ions in so-called escape directions out of the MBM becomes negligible (') because of their then large magnetic moment, so that there is a high, stable, stationary, localized fusion rate in spatial proximity of B _mιn (B-minimum) yields If Trash _mιn to a spatial zone B in the resonant volume, the magnetic field strength within the limits defined above, the accumulated magnetic moment leads even to the fact that the ions experience a force in the direction of the spatial zone of Bmm and compressed there in the opposite direction to the field gradient.This compression grows in proportion to the rotational energy of the ions and thus leads to a higher ion density the higher their rotational energy is, so that the ions with the energies of interest for fusion in higher spatially well-defined areas have a higher density be compressed as the density of the surrounding plasma This behavior not only provides great advantages compared to previous and planned fusion machines, but for the first time a really controlled plasma fusion machine, in which the fusion energy generation takes place continuously and in which the energy yield by regulating the Density of the high-energy reactants can be controlled This regulation of the density can be improved by generating alternating electrical fields of several frequencies, by order of magnitude percent different, since then the compression of the ions can be achieved over larger resonance volumes, which is due to a greater variation of the magnetic field than just plus and minus 1% and can still be completely brought into IZR with other frequencies

The efficient, selective ion heating is achieved in that the magnetic confinement of the plasma takes place in an MBM with a large HF-IZR volume, as suggested, for example, by Alton and Smithe for EZR (electron cyclotron resonance) ion sources (see reference 2 GD Alton and DN Smithe, Review of Scientific Instruments, Vol 65, S 775-787 (1994)), and was first realized by me in an EZR ion source. Such MBM are distinguished in that the resonance volume in which Bmm is constant except for deviations of plus or minus 1%, fills at least 0 4% of the total volume of the plasma chamber, whereas in previous and planned fusion machines the resonance volume was not considered at all and therefore only resonance surfaces with an extremely small resonance volume exist in a plasma chamber cylinder Long 1 and the radius r eg 1% of the total volume is achieved in a resonance volume with long 1/4 and radius r / 5, e.g. with long 1/2 u nd radius r / 2 to 12 5% and can be increased even further by further increasing these values if the necessary technical effort is accepted

Since the plasma frequency at high electron density of about 2 10 ¹⁴ cm ^{"3 reaches} the order of 100 GHz and electrical waves of a lower frequency cannot penetrate such a plasma, the HF-IZR coupling at frequencies of the order of 1-200 MHz either

(ii) or by spatially structured, magnetic HF alternating fields, which are superimposed on the MBM and induce the local electrical HF IZR fields necessary for heating in the spatial IZR areas of the plasma

(iii) or by irradiating two microwaves each, the frequencies f and f of which are above the plasma frequency and the difference frequency f -f is equal to the respective ion cyclotron resonance frequency, the electrical difference frequency amplitude in the plasma is generated about nonlinear plasma interactions, which are particularly effective in dense plasmas, so that in these cases we can speak of EIIZRH (Electrically Induced IZR Heating). The types (ii) and (iii) of selective ion heating do require large HF or microwave power, since only the induced electric field or the non-linearly generated electrical differential frequency amplitude is effective. However, the overall balance of energy transfer to the ions is significantly more favorable than previous plasma heating processes due to the exploitation of the IZR in a large resonance volume

For B _min of about 2 8 (2 0) T, deuterons (protons) with energies of 100 keV with a plasma chamber diameter of 400 mm can be very well concentrated in the spatial region Bm, whereby the energy distribution with selective EIIZRH is in no way a Maxwell-Boltzmann Distribution corresponds to what was previously assumed in fusion machines. This energy distribution can be shifted further in favor of high ion energies by the injection of ions of high energy

Since every MBM has directions of escape (cone) for ions from the magnetic structure, these directions can also be reversed and used for the injection of ions into the MBM. However, ions injected in this way were immediately left of the MBM, unless an impact with a plasma particle or the interaction with the IZR-HF field deflects them from these directions and thus leads to the trapping of the ions in the plasma. The probability of trapping therefore increases with the plasma density, with the IZR-HF field strength and with decreasing ion energy Already a few percent probability of capturing makes the ion injection into an MBM much more advantageous than the technically and economically very complex injection of neutral particles into previous and planned fusion machines.The efficiency of the IJMBM (ion injection into an MBM) proposed here is significantly increased by using negative ions, since this because of the neutralization in the outside area hen the plasma as temporary neutral particles penetrate into plasma areas, from which there are no longer any escape possibilities, before their further ionization

An MBM equipped with EIIZRH and IJMBM will therefore lead to such a high ion energy density in spatial proximity of B _mm that for the first time a stationary EPFM (energy-producing fusion machine) can be built with dimensions that are clearly behind the planned dimensions from ITER, and even offers legitimate prospects of using the clean proton-boron fusion reaction

A quasi-axially symmetrical MBM with superconducting coils as shown in FIG. 1 can be constructed as an exemplary embodiment of a functional EPFM. Superconducting ring coils (1) generate an axial mirror field, the axial component B _z (2) of which on the axis of symmetry z (3) relative to the ordinate ( 4) is plotted, here three minima (5) of B _z in the resonance volume (6) are realized The axial symmetry of the arrangement is disturbed by a magnetic multipole, here, for example, by a superconducting magnetic decapole, which can be carried out, for example, with 10 superconducting wire bundles (7) with alternating current directions, and which is necessary in order to Generate radial expansion of the resonance volume (6) and the radial increase in the amount of the magnetic field from the resonance volume (6). For example, here is either a part of the generation of an electrical IZR-HF field transverse to the z-axis in the resonance volume (6) the plasma chamber walls (8) are designed as electrodes (9), which are separated from the rest of the plasma chamber by insulators (10) and are connected together (11) in such a way that effective plasma pairs are formed, or the magnetic field structure with two antiparallel magnet coil pairs ( 12) an anti-parallel magnetic RF field is superimposed on the transverse electrical IZR RF field in the resonance volume n induced The EIIZRH is supplemented by axial injection of ions (13) against the so-called escape cone directions and radial injection of ions (14) against radial escape directions, positive or even more advantageous negative ions being used. The cylindrical plasma chamber (8) should be improved for the purpose Reduction of the plasma-wall interaction in the dashed form (15) shown only in cross-section AA is carried out, since then the maxima of the decapole magnetic field are not cut by material walls, with a further radial removal of the walls, for example in the case of the radial ion injection nozzle (16 ) should be aimed for, whenever and wherever the ring coils (1) allow this

The efficiency of the axial ion injection is increased by, for example, arranging several MBMs of FIG. 1 linearly in succession, as is shown schematically in FIG. 2. As a result, the ions which are lacking a collision or because of too little IZR-HF interaction become the first MBM leave again on the opposite side, shot into the second, third, etc. MBM The efficiency of the IJMBM is doubled, tripled, etc. in the first approximation. This arrangement also halves, divides, etc. any axial plasma losses

Such axial plasma losses can be completely avoided, for example, by arranging a number N of MBM of FIG. 1 in the form of an N-corner with N magnetic deflections by 360 / N degrees, as is shown schematically in FIG. 3. The axial IJMBM is then no longer true possible, but can be replaced by radial IJMBM

Claims

claims

1) Process for generating energy with plasma-induced, controlled nuclear fusion by generating an electronically ignited and magnetically enclosed plasma in a plasma chamber in which the vacuum necessary for the plasma generation is generated and in which the particles necessary for the nuclear fusion, such as deuterium and tritium for the D + T -> He + n reaction or hydrogen and boron for the p + ^π B - 3 x He reaction, the positive ions of which are summarized below under the term ions, are let in with sufficient density into which electromagnetic high-frequency waves are coupled and are injected into the neutral particle beams with energies of the order of magnitude at the maximum of the fusion cross section, so that the plasma particles are heated electromagnetically or by shocks up to such high energies that they achieve sufficient cross sections for energy-releasing fusion nuclear reactions, characterized that the magnetic confinement of the plasma takes place in a magnetic field structure generated by permanent magnets, copper coil systems through which current flows, superconducting coil systems or by a combination of these three methods, which is characterized on the inside by a minimum of the amount of the magnetic field B _min , which in turn is in a so-called Resonance volume is in which B ^ is constant except for deviations of plus or minus 1%, which fills at least 0.4% of the total volume of the plasma chamber, the magnitude of the magnetic field increasing in all directions from the resonance volume, so that in this Resonance volume for the highest possible Bmύ, the ion cyclotron resonance condition with the above-mentioned deviations for the plasma-imposed, high-frequency, electrical alternating fields is fulfilled, so that the ions are heated very efficiently and selectively by the resonant interaction with these alternating fields in the large resonance volume so that above all the ions gain kinetic energy and not the electrons, the large magnetic moment of the ions thus obtained in the field gradient of the magnetic field compressing the ions to a high density in the direction of the minimum of the magnetic field.

2) Method according to claim 1 for the generation of energy with plasma-induced, controlled nuclear fusion, characterized in that the high-frequency alternating electric field in the resonance volume of the plasma is generated by the plasma comprising electrode pairs of opposite and high-frequency alternating polarity. 3) Method according to claim 1 for the production of energy with plasma-induced, controlled nuclear fusion, characterized in that the high-frequency alternating electric field in the resonance volume of the plasma is generated by high-frequency, alternating magnetic fields realized with coils, which induce alternating electric fields in the resonance volume of the plasma

4) Method according to claim 1 for the generation of energy with plasma-induced, controlled nuclear fusion, characterized in that the high-frequency alternating electric field in the resonance volume of the plasma is achieved by irradiation of two microwaves, the frequencies fi and f ₂ of which are above the plasma frequency and the difference frequency f -fι is equal to the ion cyclotron resonance frequency, the electrical difference frequency amplitude in the plasma being generated via nonlinear plasma interactions

5) Device suitable for performing the method according to claims 1 to 4, characterized in that several ion cyclotron resonance frequencies are irradiated or generated so that ions of different mass or different charge or at different magnetic field strengths are heated and compressed at the same time

6) Device suitable for carrying out the method according to claims 1 to 5, characterized in that the magnetic field structure is so designed that there are several B ^ zones with corresponding resonance volumes in the same plasma chamber, in each of which or together high-frequency electrical Alternating fields are generated according to the methods specified in claims 2 to 5

7) Device suitable for carrying out the method according to claims 1 to 6, characterized in that the magnetic field structure is so designed that in the respective resonance volumes with a very slight decrease in the amount of the magnetic field to B, ™ shortly before reaching spatially des B _mιn the magnitude of the magnetic field decreases more than 1% to the value B _mιn ^'of a second spatially smaller resonance volume, which is therefore embedded in the first, large resonance volume, so that when the ion cyclotron resonance frequencies for Bπun are irradiated, the ions in large Resonance volume heated and by magnetic accumulators Moment are spatially driven to B _πun , where they fall into the smaller resonance volume with Bπun and are further heated there in compressed ion density by irradiation of the ion cyclotron resonance frequencies for B _mm '

8) Device suitable for performing the method according to claims 1 to 7, characterized in that the spatial areas of the maxima of the magnetic field along the escape directions of ions from the magnetic field structures defined in claims 1, 6 and 7 are kept clear of material walls

9) Device suitable for carrying out the method according to claims 1, 6 and 7, characterized in that ions with kinetic energies, which are of the order of magnitude of the energy at the maximum of the corresponding fusion cross section, into one in claims 1, 6 and 7 Defined magnetic field structure in the opposite direction to the escape directions from such a magnetic field structure are shot

10) Device suitable for performing the method according to claims 1 to 9, characterized in that several of the magnetic field structures defined in claims 1, 6 and 7 are spatially arranged relative to each other so that a part of their escape directions are converted into one another, this transfer by additional magnetic fields can be improved

11) Device suitable for carrying out the method according to claims 1 to 10, characterized in that several of the magnetic field structures defined in claims 1, 6 and 7, which are characterized by an axially symmetrical magnetic field axis in spatial areas at B _mιn , arranged one behind the other along this axis of symmetry are so that plasma particles, which may emerge from one of these magnetic field structures in the angular region of their axial escape cone, enter one of the adjacent magnetic field structures

12) Device suitable for carrying out the method according to claims 1 to 11, characterized in that N of the magnetic field structures defined in claims 1, 6 and 7, which are characterized by an axially symmetrical magnetic field axis in the spatial area at B _mιn , in each case by 360 / N Degrees relative to this axis of symmetry can be arranged offset one behind the other so that the N magnetic field structures form a closed N-corner structure, with at the corners Additional magnetic fields can improve the possible transition of plasma particles between neighboring magnetic field structures.

13) Device suitable for performing the method according to claims 1 to 12, characterized in that the entire system is operated periodically in time, the ions being heated in a first heating and compression phase initially with a constant magnetic field structure in the resonance volumes and in spatial areas B _mu, is compressed and is then increased, the magnetic field intensity of the total magnetic field structure or only the magnetic structure of the spatial region to B _m i _n in a second heating and compression phase, the IZR frequencies are also increased in proportion to the magnetic field strength, so as to provide maximum To increase the energy density of the ions and thus to achieve a maximum fusion energy production, which is maintained until the fusion energy production falls below a selectable threshold and is returned to the first heating and compression phase.