Patent Number: 048266469
Section: description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS It is the object of this invention to achieve large ion densities in stably-confined plasmas, held in negative electric potential wells formed by magnetically-confined electrons. This is to be done by the means described below. Electrons are injected along the field lines surrounding and entering the central (confined-plasma) volume. Injection is through point/polar magnetic cusps in an inherently confinement-stable magnetic mirror field system with minimum loss properties. Such systems are attained in the present invention by use of various polyhedral magnetic cusp confinement geometries using tetrahedral, octahedral, and/or dodecahedral configurations. Unlike the bi-conic mirror systems, such configurations have the property that coil windings may be made along their faces in such a way that no ring or line cusps are generated in the magnetic field geometry, all magnetic loss cones are through point or "polar" cusps, only. The geometries preferred for this system are all of the regular polyhedra truncated on each point, except the octahedron, which may be used without truncation (it is already the truncation of the tetrahedron). Any other polyhedron in which all the magnetic vertices are surrounded by an even number of polyhedron faces may be used as well. For such figures the magnetic field point cusps (or "magnetic poles") are to be centered on each face of the polyhedron, in an alternating pattern, so that no two adjacent faces contain cusps of like sign. The criterion for this is simply that all vertices be surrounded by an even number of polyhedron faces. FIG. 4 shows possible current paths for such a cusp field arrangement for the octahedron, and FIG. 8 shows this for the truncated cube. It should be noted that opposing faces of such polyhedra all lead to bi-conic mirror fields of opposing sign, except for the truncated tetrahedron (the octahedron), in which the opposing fields are of like sign. The octahedron thus is equivalent to a four-fold intersection of mirror-cusp-ended solenoidal fields, in which each mirror cusp provides stabilization for its adjoining solenoidal field regions. The overall geometry of the relevant magnetic field will be referred too herein as "substantially spherical" or "quasi-spherical." Attention will now be focussed on an octahedral system, starting with FIG. 4. As mentioned, the octahedron 400 depicted therein has current flowing along its edges to establish a magnetic field exhibiting point cusps on each face 410. The signs of the point cusps alternate between adjacent faces. One possible current flow pattern is depicted by the solid arrowheads shown in the drawing. FIG. 5A shows one of the current carrying elements 500 used to generate the magnetic field. Current carrying element 500 is supplied with current from a power source 510. This power source could be d.c. as in 510 or a.c. as in 515. FIG. 5B shows a typical multiple turn current-carrying coil for the same polyhedral face. It should be mentioned that each face 410 could conceivably be provided with a linear permanent magnet elements to generate the desired field configuration. FIG. 6 illustrates electric field and particle density distributions during operation of octahedral magnetic field generating or plasma confinement device 400. Details concerning the generation and configuration of the magnetic field are omitted for clarity. The electron and ion injectors used respectively to establish the negative well and "spill" ions into the well will be set forth in greater detail below in connection with the truncated cube system. As depicted in FIG. 6, electrons injected into the octahedral magnetic field source become trapped by the magnetic field to form a substantially spherical negative potential well 600. The probability of locating an electron increases toward the center of the negative potential well. Electrons are originally injected to establish the negative potential well 600 and then continuously injected thereafter to sustain the negative potential well 600. Synonyms for negative potential well would include virtual cathode or negative space charge. Once the negative potential well 600 is established, positive ions are injected into it at relatively low energies. The positive ions "fall" into the well, then increase in kinetic energy as they are drawn toward the center. The charged particles oscillate across the potential well. As the ions cross the center, they encounter and interact with other ions. It is anticipated that attainable plasma temperatures and confinement times will meet or exceed the thresholds required for useful levels of fusion reactions, in which fusion power generation is significant. This is depicted in FIG. 6 as a central region of maximum collision density 620. This collision density varies ideally as the inverse fourth power of the radius, and so is highly peaked at the center of the spherical well, although practical considerations prevent it from reaching near-infinite density as r approaches zero. The negative potential well 600 is also depicted graphically in FIGS. 7A and 7B. The diameter of the well is designated 2R. The "depth" -V corresponds to the voltage used to accelerate the electrons for injection into the cavity. Qualitative density distributions are also depicted for the "ideal" case and the "practical" case. Alternatively, ions may be injected to form a positive "virtual (anode) electrode" in the device center as described by Farnsworth and Hirsch, with electron injection in addition towards and through this virtual electrode, to form an ion-confining negative potential well within the ion-formed virtual anode. In either case ions will be trapped by negative potential wells which are, in finality, held in place stably by circulating electron currents tied to stable external magnetic fields of an appropriate polyhedral geometry which ensures low electron losses and ease of injection of electrons and ions into the system. Inertial energy and momentum content of either or both the electron and/or ion injection beams can be utilized to provide compressional pressure forces to sustain high pressures in the central plasma core of the device. The conversion of inertial energy content of injected charged particles can be accomplished in the central (convergence) region by simple (Coulombic) collisional means (which may involve the generation of multi-stream instability interactions), or in the (surface) magnetic field regions by interaction through gyration on orbits on which the particles (particularly the electrons) are trapped when injected in an annular fashion, parallel to the cusp field lines. System power balance constraints arising from pressure balance considerations may limit the maximum gain (G) attainable in the system. More detailed consideration of this issue is given below, in connection with a summary of physics phenomena which are of importance in the operation of such systems. FIG. 8 depicts a truncated cube system 800. A possible pattern for current paths along the edges is shown using small solid arrowheads. FIG. 9 provides details of electron and ion injection. In the polyhedral systems of interest here electrons may be injected either directly along a cusp axis (or axes) or in an annulus around such axis/axes. If injected in an annulus, they may be injected either with paraxial velocity (along the local cusp field lines) or with a rotational component around the cusp central axis. A negative potential well is thus formed by the injected electrons converging to and trapped within the central region of the externally-driven magnetic field system. Ions are injected to be trapped in this negative potential well. These may be injected caoxially with the electrons, in an annulus surrounding the electron beam, with or without ion beam rotation, or in a central axial beam within an annular electron injection beam, or may be injected through magnetic point cusps on faces of the polyhedral system opposing the electron injectors. In FIG. 9, numeral 900 designates a first positive ion injector. First positive ion injector 900 includes a gas inlet 910, an ionizing region 915, an accelerating grid 920 and an annular beam lens 930. Thus, first positive ion injector 900 is constructed and arranged to produce an annular beam centered on one of the axes of the truncated cube system. Numeral 940 designates a first electron injector. First electron injector 940 is also centered on an axis of the truncated cube, and is constructed and arranged to direct an annular electron beam to the center of the interior volume of the truncated cube. First electron injector 940 includes an electron emitter 950 electrically connected to an emitter power source 955, and an accelerating grid 960. This grid is held at an electric potential +V above that of the emitter, by an electron grid power source 965, thus producing a central potential well depth of -V (FIG. 7A). Additional injectors may also be provided. FIG. 9 illustrates the provision of an additional injector of each type, a second positive ion injector 970 arranged symmetrically opposed to the first positive ion injector 900, and a second electron injector 980 arranged symmetrically opposed to he first electron injector 940. The details of construction of these additional injectors will in general be the same as that of the opposed injector of the same type. Thus, these detals have been omitted from the drawing for clarity and will not be further discussed here. Details for injector placement on the surface of an octahedral system are substantially the same. FIG. 10A illustrates one possible arrangement for the truncated cube system of FIG. 9 as a heat-generating element in a power plant. Truncated cube electron confiner 800 is shown in a cross-section taken along line X--X of FIG. 9. The system is placed with its associated injectors 900, 940, 970, and 980 in an evacuated containment structure 1000, depicted as a circular shell. As shown in FIG. 10A, containment structure 1000 is heated by absorption of radiation 1100, and by collisions with particles 1200, generated by the fusion reaction occurring in truncated cube region 800. This heat is thermally coupled to a heat exchanger 1020 (section of heat exchanger shown) in which a working fluid such as water absorbs heat. The heated water is then conveyed through thermal to electric conversion unit 1010 which converts the heat energy stored in the water into electrical energy. Thermal to electric conversion unit 1010 may be any known means for converting heat energy into electricity. FIG. 10B shows one arrangement for direct electrical conversion of fusion product particle 1200 energy by causing the particles to travel outward against a positive electrical bias fVp applied to the containing shell 1000. The containment structure 1000 is evacuated through conduit 1030. The truncated cube electron confinement device 800 is cooled via cooling channel 1040. The physics phenomena which control the action of such systems allow operation over a very wide range of sizes, from a few centimeters in confinement volume radius to many meters for such a dimension. Electron surface losses through and from the confining magnetic field will limit the power balance performance (i.e., the system power gain) of such devices. However, a simple estimate of maximum potential system gain can be obtained by balancing electron injection requirements with ion makeup needs to replace ions burned up by fusion reactions in the confined core. This method ignores surface losses, and limits electron power needs to internal requirements, only. If scaling of the fusion power is constrained by limiting energy flux through the boundaries of the device, then it is possible to calculate a maximum upper limiting system gain value (G+) for any size of machine. Although unrealistically optimistic from an engineering standpoint, the results of such an analysis show absolute upper limits on system power gain. These (G+) values vary roughly linearly with system radius (R). The size of such devices can range from R.congruent.10 cm radius to a radius of several meters (e.g., R.congruent.3 m). Some crude estimates of these parameters are given in Table 1, for systems operating on DT or DD fusions. The upper limit system gains possible for use of other fuels and nuclear reactions will be less than those shown, because operation with such fuels will require larger negative electric potentials than for DT/DD. The inclusion of realistic external loss effects, and the requirements for beam injection to support central plasma core pressures will yield considerably lower practical gain values from such machines. TABLE 1 ______________________________________ ELECTRON/ION BURN BALANCE LIMIT ON POTEN- TIAL RANGE OF DT/DD SYSTEM PERFORMANCE B-FIELD REACTION DRIVING UPPER LIMIT SURFACE POWER POWER SYSTEM POWER RADIUS OUTPUT.sup.(1) INPUT.sup.(2) GAIN.sup.(3) (R) (Pf, Mw) (Pi, kw) G+ = Pf/Pi ______________________________________ 10 cm 0.1-1 2.5-25 4-40 30 cm 1-10 8-80 12-125 1 m 10-100 25-250 40-400 3 m 100-1000 80-800 125-1250 ______________________________________ .sup.(1) Surface energy flux at radius R is 0.08-08 kw/cm.sup.2 .sup.(2) negative electric potential well is about 100-200 kev .sup.(3) system power gain may saturate at about G &lt; 1000 The smallest size of practical interest is that at which the dimensions of the confining magnetic field volume are comparable to or less than 10-100 times those of the radius of gyration (gyro radius) of electrons at given energy in the confining field at the periphery (surface) of the confined volume. Devices smaller than this will be dominated by losses of electrons out through the loss cones of the polyhedral field systems. Typically, gyro radii of 0.5 mm-5 mm characterize electrons at transverse energies of about 20-50 kev in magnetic fields of 1-5 kilogauss. Thus, electrostatically confined plasma systems of this type whose confinement volume radii are much smaller than about 10 cm will suffer from greater relative electron losses than will larger systems. Devices smaller than this will be dominated by higher relative power needs (than for larger systems) for cusp field magnets, and for requirements of central core pressure balance, rather than by electron losses due to injection requirements for surface loss makeup to maintain negative potential well generation capability. These latter power losses will dominate the real power balance gain in larger devices. Their assessment can be made using electron transport coefficients from previous work in fusion plasma physics. Jacobsen et al have analyzed electron and ion losses in tokamak devices using essentially all of the models for electron transport scaling laws which are in current use in fusion research work. Robert A. Jacobsen, Carl E. Wagner, and Richard E. Covert, "System Studies of High-Field Tokamak Ignition Experiments", J. of Fusion Energy, Vol. 3, No. 4 (1983). Electron losses through the cusp loss cones can be minimized by appropriate injection/grid structures, geometries, and potentials. However, collisional losses of electrons within the peripheral region of magnetic field surrounding the central plasma are an unavoidable result of the need for significant surface electron densities to maintain the negative electric potential well required to confine ions at useful densities within the magnetic field structure. This surface collisional electron loss rate sets the minimum input power level of real devices, and hence limits their power gain. The power density of operation is given by the product of ion density squared and the fusion cross-section product with the ion speed within the well. Since both the speed and cross-section increase with increasing well depth (in the range of interest here) the power density will be determined (strongly) by the depth of the confining electrostatic well in the central plasma region. Larger well depth will lead to larger power density for the particle reaction power. If this power output is limited to yield a constant surface flux of energy generated within the system, the required confining well depth will become smaller as the device size is made larger. The ion density which can be sustained in such a system will be limited by the ability of the fields (both electric and magnetic) of the confinement system to support the pressure required by the ion density at the temperature of operation (i.e., at the "temperature" of particles at the energy of the well depth). The kinetic pressure p=nkT of the plasma must be balanced by an external pressure force to sustain it stably. As often pointed out, the electric field (E) required to "hold" a plasma ion density (i.e., by .beta.E**2/8 .pi.=nkT) sufficiently large to yield useful fusion power density does not seem practically attainable. See, e.g., S. Glasstone and R. H. Lovberg, Controlled Thermonuclear Reactions, D. Van Nostrand Co. Inc., Princeton, 1960, Sect. 3.13. Here .beta. is the "efficiency" of use of field energy density to sustain particle energy density. Similarly, for magnetic confinement (e.g., by .beta.B.sup.2 /8.pi.=nkT) either the volumes are so large or the magnetic coil currents are so large that net power balances appear questionable. In the device concept and invention claimed herein these limits are overcome by the use of the circulating electron and ion current, through the confining electrostatic potential well region, as the means to couple momentum pressure support from a high pressure central core to a low pressure external surface. In effect the circulating or oscillatory centrally-convergent currents act as a special type of "gas" which exhibits a strong radial pressure gradient such that its pressure is very large at the center and small at the periphery of the electrostatic well region. Analysis of the current requirements for pressure balance shows that the net system gain G (for given surface injection current density) is related to the cavity current amplification factor G.sub.j and the system characteristic radius by G=C1 (R**.sup.5) (Gj**.sup.2). The coefficient C1 is found to be approximately C1=3.0E-17 /cm5 for R in cm. For a "break-even" system, G=1, and a current amplification of G.sub.j= 10E5 is required for a system radius of R=20 cm. Conversely, without any current amplification at all in the system, G.sub.j =1, and G=1 will be attained at a system radius of R=2000 cm=20 m. Amplification factors of 1E6 and higher have been attained in a variety of electronic high power tube devices. FIG. 11 shows the current amplificaton factor Gj required for a range of net system gain 1&lt;G&lt;100 for two reactive charged particle fuels, as a function of system size, R. Also shown are the conditions required for attainment of the BHE ("black-hole-effect") previously described. Another physics feature of importance in system operation is that the fusion products will, in general, not deposit their energy in the plasma region (as in the case in "conventional" concepts for fusion), but will escape from this region to the structures and surfaces bounding the polyhedral magnetic/plasma system. In this escape, these particles will leave as positively charged ions, thus increasing the net negative potential of the plasma region. Each fusion event will cause an increase in the well depth which is confining the reacting ions, hence will cause an increase in the particle density and resulting inter-particle reaction rate which will, in turn, cause a further increase in the negative potential, the well depth, etc., etc. The onset of fusion reactions in a negative potential well of the type contemplated herein will thus initiate a self-generating process to increase the well depth and thus to increase the fusion rate. Under certain special conditions (of total recirculating ion current) it is possible, but not certain, that--once started--a reacting assemblage of this type could become self-sustaining without any further excess external electron injection, beyond that needed for balance with the ion injection rate itself. In any case, this self-generating-well effect might allow the reduction of electron injection for well sustenance, and thus could result in a reduction in the externally-supplied power required to drive the electron injection system. For systems in which the electron-injection-generated well depth is kept the same for all system sizes (i.e., ignoring the scaling of minimum required well depth with system size, discussed previously, and ignoring the potential reduction in electron driving power which may result from self-generating wells, discussed above) it is possible to estimate the electron surface leakage power losses by use of the standard coefficients (mentioned above) for electron transport. Altenatively, electron surface losses can be estimated by use of the standard equations for electron thermal conduction transport across magnetic fields. D. L. Book, 1980 Revised NRL Plasma Formulary, Office of Naval Research, Wash., D.C. The loss rate of electrons will depend on the current amplification which is extant in the machine at the conditions of operation. Since this is set by pressure balance requirements, its choice is tied to the fusion reaction power output desired from the system. Analysis shows that the surface power loss due to electron collisional escape through the confining polyhedral field structures is set entirely by the local electron density in the surface field region, not by the injection current. For this reason, nearly an electron current multiplication is possible; however, the system power balance--and therefore its gain--will be fixed by this surface loss rate, rather than by the electron injection needed to make up for fusion-reacted ion burnup, used as the basis of Table 1. Analysis of such losses shows that the energy flux (Pe watts/cm.sup.2) of electrons escaping through the surface field region is just: Pe=C2 (n.sup.2 /Bwhere n is electron density in electrons/cm.sup.3, and B is the surface layer field strength, in Gauss. With this, it is found that losses can be limited to 1-25 watts/cm.sup.2 with modest fields, while retaining electron densities large enough to ensure current amplification values of about 1.0E5&lt;Gj&lt;1.0E6, and larger. Operation of the system concept herein has been discussed as though always in a steady-state mode. This is not ncessarily the only way in which such systems may function. In particular, once a central electrostatic potential well is established, and ions are trapped therein, it may prove possible--and useful--to pulse the well to still greater depth by the rapid injection of energetic electrons (e.g., as from an electron accelerator) into the confined ion region. By this means it may prove possible to ignite a fusion-burning plasma within a potential well which then becomes self-sustaining, as discussed previously. Another area in which oscillatory or dynamic effects may affect system performance is related to the effects of the geometric structure of the surface-confining magnetic fields on the shape and depth of the electron-generated internal negative potential well. Consider a magnetic field geometry, for example, in which the electron-reflecting field surfaces are planar in a cubical array. In this (unrealistic and undesirable) geometry injected electrons will never focus within the system and thus can never produce a negative potential well in the center of the cube. Rather, the potential well will tend to be uniform and the same everywhere, for electron injection with uniform current density over each surface. In contrast, electrons injected with uniform surface current density into a perfect spherical geometry will oscillate radially across the sphere, and will reach much higher density at the sphere center than at its surface. This will result in a deep central negative potential well which can confine ions in the system. In the multi-faceted polyhedral magnetic field geometries of interest here for electron confinement, the degree to which the confining fields appear spherical or quasi-spherical to the electrons will depend upon the fineness of surface structue, and the time-averaged field strength and direction "seen" by electrons transiting (being reflected by) the field. An electron moving radially outward from the well center will encounter a field of increasing strength as it approaches the confinement volume boundary. Its energy of motion, and thus its radical speed will likewise increase as it "falls" back up the potential hill which has been created by its injection. By proper choice of a sufficiently large surface magnetic field strength, the radius of gyration of such electrons can be made small compared to the dimensions of the system, and the electrons will be "reflected" and returned to the system. The vector direction of their returned motion will depend upon the field angles seen by the electrons in or during the reflection/turning process. If the magnetic fields are maintained at constant levels (i.e., dc current driven, or fixed permanent magnets), the field strengths and angles will not change, and the reflected electrons will "scatter" off the field surfaces with a certain angular dispersion or spread. This spread will always result in a reduction of the well depth attainable in such a system as compared with that in a perfect spherical system. However, it is possible, in principle, to cause the fields to oscillate in such a manner that the electrons will perceive a time-averaged field direction which more nearly approximates a sphere, while still retaining the properties of MHD stability and low losses through point cusps. This can be done by utilizing two (or more) interlocking polyhedral geometries, and modulating the fields at a frequency sufficiently high that they oscillate through many cycles in one transit time of an electron. This is depicted in FIG. 12, which shows a structure resulting from the superposition or interlocking of an octahedral geometry with a truncated cube geometry. At such conditions, the electron will "see" the cycle-averaged field strength and direction of the interlocked polyhedral system; and this can be made to approximate a sphere quite closely. This is the general approach used by Keller and Jones (mentioned above), who studied rf confinement and heating of neutral plasmas in an rf-modulated ocahedron interlocked with a truncated cube. In order to make this approach fully effective, the field vectors should have the same sign locally in each of the polyhedral structures as they proceed through each oscillation cycle, and their amplitudes interchange. Although this was not the case in the Keller and Jones work, they still observed spherical electric potential waves in their system. Electrons at the confined volume surface region will be moving at maximum radial speed, hence will have a very short time for gyration/reflection in this region, given a field of sufficient strength, as required. To produce a quasi-spherical effective field for such electrons requires field driving modulation at a frequency higher than this gyration frequency. Conversely, near the center of the well where the magnetic field is small, the electrons possess and the electrons possess very small energy of motion, and are moving at relatively slow speed, hence the field oscillation frequency required for apparent quasi-sphericity is much lower than that required for electrons at the larger radii nearer the system surface/boundary. In effect, the frequency of modulation will set the radius region at which effective quasi-sphericity will become effective to enhance electron confinement. As a final consideration, note that the degree of discreteness of even a constant strength (i.e. non-modulated) field structure seen by the electrons depends upon their radial position as well. Near the surface field-generating-coil region the local field strengths are large, and the topographical structure of the fields will follow that of the mechanical current-carrying structures which produce them. Deeper into the system, at smaller radii, the discreteness of structure becomes smoothed out, until even dc fields appear nearly-spherical at and around the center. The modulation of fields, the choice of frequency, and the interlocking polyhedra, as described above, are all controllable by design, and available to improve the confinement properties of the system. Also of potential interest is the possibility of modulating the electron (and/or ion) injection beams to produce a modulation of the internal potential well depth, and thus of ion confinement and reaction rate. FIG. 13 graphically illustrates the posibility of making the well depth oscillate. In the situation shown in FIG. 13, the well depth periodically varies between -Vo+V.sub.E and -Vo-V.sub.E with time. Thus, the variation can be expressed as -(Vo+V.sub.E)(sin wt), where w is the frequency of oscillation of the well depth. The degree of modulation of the confining electrostatic potential well depth will depend upon the radial oscillatory current amplification (Gj). If this is large, a given modulation of input beam will yield only a small fluctuation in well depth, unless the modulation is locked to a transit time frequency of the particles oscillating in the well. With such resonant locking, it may prove possible to achieve large well fluctuations even with small modulation of input injection current. An eventual limit on this behavior will be set by the loss of coherence in beam/plasma resonance due to scattering in the transits of the beam after injection. Conversely, if Gj is small, the well depth and reaction rate can be caused to fluctuate directly over a considerable range. Such modulation of reaction rate can also produce modulation of system electric radiative power output, both from plasma oscillations coupling within the central core region, and from the production of large oscillating potentials on surrounding or containing structures. Plasma core oscillations may also be stimulated by externally supplied radio frequency power through antennas radiating spherical rf waves into the plasma region. Such rf modulation (at injection beam frequencies, or harmonics thereof) may prove useful to enhance the oscillatory output of a system which is driven only by injection beam modulation. Any coupling of direct electrical power generated by the plasma into such rf wave structures would allow the device to function as a self-powered rf amplifier. These modes of operation are not necessary to the conception of the device as an invention in the art, but may be of interest as alternative or in addition to steady-state methods of operation. The invention discussed herein offers the ability to create nuclear fusion reactions in a wide variety of fuels. As discussed above, these range from the least-tehcnically-demanding DT system, to the least complex and least costly DD system, to the radiation-free higher-Z fusion fuels (e.g. pB11, et al). Civil/commercial applications will favor the use of DD systems for the production of low-cost steam. Cheap steam can be used in conventional means for the generation of electricity, desalination of sea water, production of synthetic chemical fuels (e.g. alcohols, coal liquiefaction, etc.), chemical and materials processing, etc. Some exemplary reactions which may be feasible with the present invention proceed as follows. First, D and T can be made to yield DT fusion reactions according to: EQU D+T.fwdarw.He4 (3.52 Mev)+n (14.1 Mev); (1) (Q=17.62 Mev), and confinement of D alone can be made to yield (with equal probability) DD fusion reactions as: EQU D+D.fwdarw.He3 (0.82 Mev)+n (2.46 Mev); (2a) (Q=3.28 Mev) EQU D+D.fwdarw.T (1.01 Mev)+p (3.02 Mev); (2b) (Q=4.03 Mev) The T produced (in Eq. 2b) will react according to Eq. (1) with the D in the plasma, if the fusion product tritons (T) are contained in the system. In general, in the systems considered, most of the energetic (Mev+) fusion products will escape the confined plasma volume. The He3 produced (in Eq. 2a) will also react, if confined, by: EQU D+He3.fwdarw.He4 (3.67 Mev)+p (14.7 Mev); (Q=18.37 Mev) (3) Other reactions of interest include: EQU p+Be9.fwdarw.He4 (1.3 Mev)+Li6 (0.9 Mev); (Q=2.2 Mev) (4a) EQU p+Li6.fwdarw.He3 (2.3 Mev)+He4 (1.7 Mev); (Q=4.0 Mev) (4b) EQU p+B11.fwdarw.3 He4; (Q=8.7 Mev) (4c) It is useful to note that reactions (3) and (4a)-(4c) yield only charged particles as their fusion products. Thus they are radiation-free with respect to direct penetrating radiaton products (e.g. fast neutrons). Table 2, below, summarizes the range of negative electric potential well depths required for the confinement of sufficient ions for useful reaction rates of the above reactions, for monoenergetic ions, and for equilibrium Maxwellian energy distributions. TABLE 2 ______________________________________ RANGE OF NEGATIVE ELECTRIC POTENTIAL NEGATIVE ELECTRIC POTENTIAL NUCLEAR FUSION WELL DEPTH REACTIONS Monoenergetic ions Maxwellian ions ______________________________________ D + T 15-100 kev 10-200 kev D + D 30-200 kev 20-400 kev D + He3 50-350 kev 30-600 kev p + Be9; p + Li6 100 kev-700 kev 60 kev-1.2 Mev p + B11 200 kev-1.4 Mev 120 kev-2.4 Mev ______________________________________ DD systems do not require the use of externally-supplied T, and thus do not require breeding blankets of Li (in which T is produced by n capture in Li6), as do closed-cycle DT systems. Systems operating on D alone will generate a significant output of neutrons at moderate energy (about 2.5 Mev; see Eq. 2a) in the DD fusion process. However, if the T produced in the DD reaction mix (see Eq. 2b) is not contained or burned within the plasma, no energetic 14 Mev neutrons will be produced and the radiaton hazard will be less tha (1/10) that of a DT system (see Eq. 1) for operation at the same gross fusion power level D (H2) is the least costly fusion fuel except for p (H1), which requires more expensive B11 or Li6 to generate radiation-free power. This fact and its relatively low radiation hazard potential make it a good candidate for use in civil/commercial/industrial profit-making energy plants. In such energy plant use, it is contemplated that the fusion device willbe sufficiently small in size and low in cost that it can be operated to destruction or end-of-life without on-line maintenance, and may be removed, disposed of and replaced at such time. In this fashion, its in-plant application method resembles that of other compact fusion devices. See, for example, U.S. Pat. No. 4,367,193, issued to the present applicant. However, except for use of DT fel, no Li blankets are needed, and the fusion unit to be removed and replaced here need be only the magnetic coil system of the current invention, not necessarily including its ion and electron injectors. Such removal and replacement is not unique to fusion plants; similar exchange of power sources is made in jet aircraft whenever the turbojet engines reach their point of allowable wear or end-of-life, and to electric light bulbs which are replaced when they fail while the electric power plant supplying electricity to their sockets continues to operate. As previously noted, DD fusion systems may produce energetic DT fusion neutrons (14.1 Mev) if the T produced in half of the DD fusion reactions (Eq. 2b) is captured and fed back into the plasma region to be burned. Since the DD process, in the invention discussed herein, does not require T for its startup or its continuation, no breeding of T is necessary for such DT reactions in a DD system. Thus all of these energetic neutrons, as well as all of those lower energy neutrons resulting from the other half (Eq. 2a) of the DD fusion process, are available to be used for the nuclear breeding of T or of fissionable fuels, or for the burnup of radioactive nuclear wastes. Thus, any DD-driven plant can also be designed to produce neutron-generated products as well. For example, a plant producing electricity might also use its output neutrons for the transmutation/burnup of fission product wastes from conventional nuclear reactors. It is estimated that DD systems which burn all of the T they produce will be capable of breeding 2-3 times as much transmuted product as is potentially possible in conventional fusion reactor plant concepts, and up to 20-50 times as much as from fission breeder reactors (e.g., Phenix-II of LMFBR). Also as noted before, nuclear fusion reacting systems of the type herein will not generally confine the charged particle products of the reaction. These all appear with sufficient energy to escape the externally-driven ion-confining electrostatic potential well, and will not be confined by the magnetic fields used to support the electrons required for maintenance of this electrostatic well. They may be collected on the walls or on any other structure of the system outside the confined ion-plaasma region. Since they are charged particles this method of operation offers the prospect of the direct conversion of their energy to electricity, by the imposition of a high positive potential on these surronding walls/structures. Thus it is another object of this invention to allow the production of electrical energy by direct conversion of the energy of fusion product particles from their generation in devices of the type considered herein. In DD systems the He3 and T produced can be collected and recycled back into the system for further fusion reaction and additional energy release with the D ions therein. Alternatively, the He3 and T products escaping the system could be collected and used as fusion fuel in DT or DHe3 fusion systems located elsewhere. Given a fusion system capable of burning DD, there appears little incentive to use DT fuels for civil/commercial applications. Conversely, burning high-neutron-output DT offers certain new and unique capabilities in military systems not previously attainable by any other means, and such systems seem especially useful for military applications. Fusion by use of DT fuels can be accomplished in the system of the invention described herein with smaller central electric potentials than are needed for DD (or for any other fusionable fuels). Such DT fusion systems have the property that 80% of their output energy appears as 14.1 Mev neutrons. This highly radioactive neutron output makes then of potential use for various national defense missions, e.g. as small mobile ground-based radiation weapons, for remote irradiation of military targets with thermonuclear neutrons. Their small size, low power consumption, and mobility also make such systems uniquely suited to a variety of military uses in the space environment. These include systems for remote inspace irradiation and radiation-counting inspection, radiation damage or kill of opposing spacecraft and equipment, etc. Calculations of neutron spectral output from such systems show that their spectral energy distribution is similar to that from relatively "clean" "hot" thermonuclear bombs, thus they could also be useful for some aspects of TN weapons output simulation. The large output and low cost of the energetic neutrons which constitute the output of DT burning systems make these ideally economically suited for use as neutron sources for the breeding/production of a variety of nuclear fuels and other isotopes. These include reactor grade nuclear fuels (e.g., approximately 3.5% enriched in U233 or Pu239, etc.), weapons-grade fissionable material, low-cost T, and a variety of special trans-urani isotopes which have unique uses in nuclear weapons systems. Finally, if negative potential well depths of 400-800 kev can be produced and maintained stably, as the current invention indicates, it is possible to burn non-radiative or radiation-free fusion fuels such as pB11 or pLi6, which yield only He4 and He3 as their fusion products. Although such special isotope fuels are more costly than DD alone, the radiation-free character of the systems in which they operate makes these of unique vale and application for various military and space missions. Among these are modulated self-powered microwave power generators with power output much larger than modulated input power; space propulsion engine systems for rocket propulsion at very high performance levels, exceeding conventional means by factors of 10-100; small, non-hazardous and light-weight space electric power systems; mobile military power plants; surface ship and submarine propulsion systems which do not require any significant shielding; and even radiation-free unshielded propulsion systems for aircraft. In any of these systems, the fusion products may be allowed to escape the confined plasma region and their energy may be converted directly to electricity, if desired. In general, the large gain (G) of these systems, even at small sizes (see Table 1), makes their application to systems of modest size and scale quite straightforward. In fact, the smallest radiation-free systems could be used for a variety of civil applications on a local level; e.g., power units for apartment complexes, small housing developments, single manufacturing plants of modest size, etc. Other civil/commercial applications are obvious for radiation-free systems; including ship propulsion, prime power for railroad engines, and selected steam-generating and/or electric power production plants, where special isotope fuel costs are not significant compared to local costs of hazard prevention for radioactive fuels (especially DT). In conclusion it is worth noting that the basic device, as conceived, is not necessarily an "ignition" device in which a certain set of conditions must be achieved in order that the fusion reactions will become self-sustaining. Rather it is inherently a power amplifier, in which (small) electric power is provided to the magnetic field coils and electron and ion injectors of the system, and (large) fusion reaction powers are induced and caused to continue steadily and stably within the machine's confined plasma volume. This feature is a natural result of the facts that: (a) electrons have gyro radii much smaller than the device radii; (b) fusion fuel ions have gyro radii comparable to the device radii, and; (c) fusion products have gyro radii much larger than the device radii. All of this ensures that: (a) electrons will be well-trapped by the magnetic fields of the device; (b) plasma ions will not be trapped by these fields but, rather, by the elctrostatic fields set up by the trapped electrons, and; (c) fusion product ions (e.g., He4, He3, T, etc.), with multi-Mev energies, will simply escape from the system entirely, carrying their energy with them. Because of this latter feature, the device may exhibit an "ignition-like" property, in which the initiation of significant fusion reactions can result in the ejection of large numbers of positive charges which, in turn, increase the fusion reaction rate by deepending the electrostatic well confining the fusion reactive plasma. The richness and diversity of fuels and processes for fusion power production offered by this new and novel means of confinement and of adding energy to plasmas and charged particles offers many new possibilities for unique applications to conventional and non-convetional energy plants. In addition, entirely new types of energy/power systems for civil/commercial, space, and military uses are made possible by this device. It will be apparent that the broad teachings of the present invention can be profitably applied to specific embodiments and applications far beyond what is set forth above for the purposes of illustration. The present invention should therefore not be in any way deemed limited to such specific embodiments and applications, but should instead be deemed fully commensurate in scope with the following claims.