186 Fusion Energy: General O P Bogdan C. Maglich, Dan W. Scott†, Tim Hester, James Nering California Science & Engineering Corporation
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building ionization collisions which counter the neutralization, σ = 107 b. At D+ energy ~200 KeV, charge Invention of strong focusing and colliding beams (1972) transfer and ionization are equal. Above 200 KeV, the has rendered obsolete confinement of ions in plasmas (1954). neutralization–to–ionization ratio reverses itself. Ionization Unlike random motion, colliding beams are ordered systems becomes 102 times greater than neutralization at ~ 1MeV and as such, subject (1) to magnetic focusing forces, (2) to where confinement times of 20s has been routinely achieved. external control by a combination of external periodic or aperiodic signals and (3) time average neutralization via oscillating electron clouds. Energy confinement time of colliding beam systems ranges from 7 hours (Brookhaven) to 3 months (Fermilab, CERN) because they operate above the Physical meaning of the reversal is that the ion collision critical energy ~ 200 KeV 3 – We present a compact colliding velocity in lab be greater than ‘atomic unit of velocity’, vau = beam fusion test breeder reactor that stored self-colliding 2.2 x 106 ms-1, which is the orbital velocity of the electron in deuterons of 725 KeV with an energy confinement time of 24 H atom2. s, resulting in copious production of tritium and helium-3 isotopes.
In his Nobel lecture1, Kapitza posited that physics issues of fusion reactor had been resolved but – in analogy with nuclear reactors - there is an unknown critical size of reactor to be determined solely by the engineering, which has not been reached; its practical dimensions, may turn out to be too large to make the reactor feasible. Although critical mass, rather than size, is the nuclear reactor parameter, in the absence of any fusion reactor theory, Kapitza’s critical size argument has been the lodestar of global fusion programs. It is shown here that thermonuclear ignition was not achieved for the past 60 years because all tokamak experiments were conducted at the thermonuclear ion energies, 10-40 KeV. Largely overlooked detailed atomic cross section measurements at Belfast2 have shown that at these thermo- nuclear energies, magnetic confinement is prevented by the hitherto ignored charge transfer collisions (CT), a class of atomic reactions between ions and neutral atoms or molecules (‘neutrals’). CT tends to destroy beams and plasmas by electrically neutralizing the hot ions within, with Fig. 1. First High-Energy Fusion Test Reactor Auto- 9 12 a cross-section, σ10 10 barns, which is 10 times that of Collider Migma IV in which 725 KeV D+ beam was stored 2 DT fusion; it is also 10 times larger than that of the plasma- with energy confinement τE = 24 s.
Transactions of the American Nuclear Society, Vol. 112, San Antonio, Texas, June 7–11, 2015 Fusion Energy: General 187
We will refer to the ion energy corresponding to equal cross sections, σ10 = σ01, as to the critical energy for magnetic confinement, approximately given by:
EC 25kM KeV (1)
where: 25 KeV is lab kinetic energy of ion with mass M=1 and velocity vD = vau; M = average ion mass in a.m.u., and k = empirical factor for difference between vau and vD at σ10 = σ01. Empirically k 2.5 i.e. critical velocity vC 1.4 vau.
Fig. 3. Neutralization barrier. Reactivity ratio neutralization: ionization = U vs. D+ energy (Lab). Ion confinement is forbidden in ITER between 0.40 KeV and critical energy, EC = 200 KeV but viable (U << 1) at TD >> 200 KeV. For the past half-a century, it was assumed that U was the dotted line “assumed” because the dominance of ionization was correctly measured at above 200 KeV.
Using ITER parameters in Figure 1B, TD=10 KeV, p = -3 -13 2 -1 10 torr, < σ10v> = 10 m s , we obtain
7 E 5.97 10 s (2)
It follows from Fig. 2 and Eq. (2) ~106 times shorter than -1 thermalization time constant, τth ~10 s. Maxwellian plasma cannot be formed. Burnout is not possible. Thermonuclear DT fusion neutrons cannot be produced. Fig. 3 display measured τE in Auto-Collider a.k.a. MIGMA Reactor with 725 KeV D + D with charged molecular ion injection at energies above Ec, together with the calculated curve. Measurement of τE via RF amplitudes of is shown in Fig. 4. It is evident that
E 24 4 s. (3) This is the longest τE ever observed in any fusion device. + Trapping of D+ ions by dissociation of D2 beam at the center of Migmacell IV shown in Fig. 5. Copious production 3 Fig. 2A. Neutralization and Ionization cross sections. Top of tritium and He is observed and shown in Fig. 6. Practical application of the colliding beam fusion reactor is that the (solid): CT σ10 vs. TD (KeV). (dash): Ionization σ10. Lower market price of T and 3He is $3.5x104 and $7.4x104 per gram. trace (dash-dot): σ for T(d, n)α. Bottom: Ratio σ10:σ01. 1B. Other applications including medical isotope production wil Same as 1A for Reactivities. be presented.
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through stored ions5 took over. [Phys. Rev. Lett. 54, 769 (1985); US patent 4,788,024 B. Maglich and S. Menasian]. Auto-Collider is shown in Figure 1.
Triple product reached was of the order of magnitude of 24 20 -3 that in TFTR :TDnDτD =5 10 KeVm s (Auto-Collider 11 20 -3 Migma IV ); TDnDτD =5 10 KeVm s (TFTR24) where 16 -3 TD = 725 KeV, nD = 3x10 m , τE = 24 s for Auto Collider; “global τE” is used in TFTR.
Table I. Observed τE in above EC experiments with charged (molecular ion) injection. Auto- Auto- Collider C0llider OGRA DCX-1 MIGMA MIGMA III IV Ion 1.0 1.0 Energy, 400 500 10 600 725 15 Ti (KeV) τE Expected 0.2 3 5 19 (s), Eq. (7) τE 2.0 2.0 2.0 Observed 0.2 0.1 2.0 0.3 1 .0 0.3 24 4 (s)
Fig. 4. Observed vs. calculated ion energy confinement 3 + + time, τE, from TD=1 to 10 KeV, with charged D2 and H2 beam injection. Solid line: Charge transfer only. Dashed line: Charge transfer -ionization interaction. Vacuum pressure p = 5 10-9 torr. Experimental data OGRA, DCX, Auto-Collider MIGMA III and MIGMA IV3-5. Fig. 4B. Calculated ion energy confinement time, τE, with neutral beam injection in ITER. Solid line: CT only. Dashed line: Vacuum pressure P =10-3 torr. For pellet (solid) injection, multiply axis by 10-5.
Fig. 6. + Cross section through z=0 plane. A 1.45 MeV DC D2
Fig. 5. Measurement of ion energy confinement time τE beam, 0.5 mA, is injected into central of symmetry of a weak focusing NiTi magnet Bz = 3.2 T, resulting in Lorentz and = 24 4 s. Amplitudes of radial and axial RF spectra + produced by 725 KeV self-colliding orbits of D+. Injection collisional dissociation into D self-colliding orbits of 725 KeV. CEND = charge-exchange neutral detector; Ti, of D2 beam of 1,450 KeV, 0.5 mA, stopped at 8 sec; non- + linear stabilization done by electron cloud oscillations titanium sublimator pumps; D , orbits of trapped ions.
Transactions of the American Nuclear Society, Vol. 112, San Antonio, Texas, June 7–11, 2015 Fusion Energy: General 189
Copious production of 3He and T was observed by measuring radioactive DT fuel replaced with charged, two peaks in proton energy spectrum from d(D, T)p25. NB: nonradioactive deuterium; large pulses replaced with steady- CM energy of 725KeV on 725 KeV D+ beams corresponds to state DC or AC modulated fueling, giving rise to beam on target energy of 3.4 MeV, at which DD reactivity > compact aneutronic reactor with direct conversion into RF DT reactivity. Refs. 3, 4. power. Genesis of the omission of the largest atomic reaction from Lawson Criterion was discussed with Lawson in the context of Generalized Criterion6,7, according to which 12 terms were missing from the Criterion. Lawson drew our attention to his introduction which clearly stated that his Criterion was only a theoretical paper designed for “idealized conditions…to illustrate the essential features of the problem, and is neither rigorous nor complete. The assumptions made are in all cases optimistic, so that the criteria are by no means sufficient for the successful operation of a thermonuclear reactor.”9
This work was Presented to Fusion Energy Sciences Advisory Committee, US Department of Energy on 11/11/14; summary reported at T.E.A. Conference 6, Chicago, 5/30/14. Ref. 38. †Co-Author is deceased. * Maglich BC, Menasian S.: U.S. Patent 4,788,024.
1. Kapitza PL - Nobel Lecture: “Plasma and the controlled thermonuclear reaction"; Nobelprize.org. Nobel Media AB 2014. Web. 29 Sep 2014. Fig. 7. Copious 3He and T production in Auto Collider 2. Gilbody HB: Charge exchange in collisions between test form reactor Migma IV. (A) Observed proton energy multiply charged ions and neutral hydrogen; Physics Scripta, 23, distribution from D + D T + P + 4 MeV is a superposition 143 (1981). Ion-atom collision measurements relevant to fusion of beam-on-gas and beam-on-beam (solid and open squares). plasmas. XIX Int. conf. on the physics and electronic and atomic ՜ collisions; Whistler, AIP Press (New York) pp.19-38 (1995). (B) Difference between experimental points (closed squares) 3. Salameh Al et al: Experiment with stored 0.7-MeV ions: and curve as function of the colliding beam factor f which Observation of stability properties of a nonthermal plasma; Phys. ranges from 1 (target at rest) at the beam-on-gas maximum to Rev. Lett. 54, 769 (1985). 4 (crossing angle 180 degrees) at the beam-on-beam 4. Maglich B, Norwood J: Aneutronic energy, NIM A 271 maximum. Estimated luminosity: 1-288 (1988); Inst. Advanced Study Princeton Symposium, (North- . Phys. Rev. Lett. 54,769 (1985). Holland Physics Publishing Division). ସଷ ଷ ଶ ܮൌ͵ൈ 5. Maglich BC, Chang TF: Stabilization by electron ͳͲ Τܸሾ݉ ሿܫ oscillations of stored ions at densities in excess of space-charge limit; Phys. Rev. Lett. 70, 299 (1993). Maglich BC, Menasian S.: U.S. Patent 4,788,024. We prove here the existence of critical ion energy, Ec 6. Maglich BC, Miller RA: Generalized criterion for 200 KeV, above which ion magnetic confinement is feasibility of controlled fusion and its application to nonideal dd classically stable; and below EC, ions are de-confined by their systems; J: Appl. Phys. , 2925 (1975). neutralization via atomic charge transfer collisions with 7. Treglio JR: Generalized criterion for feasibility of D-T giant cross-section, 109 barns, 100 times greater than that for plasma fusion; J. Appl. Phys. 46, 344 (1975). ionization collisions that counters neutralization. Below EC, 8. Maglich BC, Hester T, Srivinivasan M: Production of Tritium at Zero Cost in Blewett strong-focusing self-collider; North neutralization sets limit to classical ion confinement time τE < 10-6 s vs. > 1 s required for thermonuclear ignition. This American particle accelerator conference, Sept. 29, 2013. 9. Lawson, JD, Proc. Phys. Soc. B70, 6 (1957). may explain why past experimental fusion reactors, operating at thermonuclear energies 10 - 30 KeV, did not ignite. In contrast, at energies above Ec, ionization prevails; stable confinement of 20 s was routinely observed with charged injection near ~1 MeV. To render a reactor viable, e.g. ITER, ion energy must be increased to ≥ 1 MeV; neutral
Transactions of the American Nuclear Society, Vol. 112, San Antonio, Texas, June 7–11, 2015 Transactions of the American Nuclear Society, Vol. 112, San Antonio, Texas, June 7–11, 2015