Preliminary design calculations for a field-reversed mirror reactor

Field-reversal experiments in the mirror fusion test facility (MFTF)

“…It is important, however, to keep this optimistic possibility in mind. The plasma size and the magnetic field are only factors of 2 to 4 less than the corresponding parameters for the prototype op timum FRM reactor, 5 and they are factors of 2 to 4 greater than the present 2XIIB experiment. If it becomes possible to run the MFTF in this longterm, sustained, field-reversed mode, then such ex periments would be an important intermediate step towards a prototype FRM ret-tor.…”

“…The highest value of the ordinate of Fig. 4 is unity, corresponding to a mirror ratio of R m = 2; this is much higher than the lower limit of the vacuum mirror ratio that was used in the initial FRM reactor studies 5 (R m > 1.0001 there). However, for a better comparison with these studies, one should pick a point on the axis of 2XIIB or MFTF which is closer to the plasma.…”

Field-reversal experiments in a neutral-beam-injected mirror machine

“…13. The mean-ion-energy confinement time is defined to be the total plasma ion energy divided by the trapped neutral-beam power: trap beam power (7) where /ndl = \/5r R p n(0) is the line density measured through the centre of the plasma. The trapped beam power contains contributions from ionization of the neutral beam and from charge-exchange replacement of a plasma ion by a beam-injected neutral: plasma as charge-exchange neutrals with mean energy Ej.…”

“…Fokker-Planck calculations of classical mirror transport with all of the plasma confined on open field lines predict Q values close to unity [6]. A preliminary study of a field-reversed mirror reactor (FRM), in which the bulk of the plasma is confined on field lines that are closed by plasma diamagnetic currents, predicts Q « 5 [7]. The concept of the FRM differs from the earlier Astron scheme [8] in that field reversal is maintained by bulk plasma diamagnetic currents rather than by a separate layer of energetic electrons or ions.…”

Particle orbits in field-reversed mirrors

“…(In fact, a gyroradius/ plasma radius in this range is thought to be necessary for stability.) This has the advantage of allowing a smaller-size device [4][5][6] while employing simpler injector technology. Indeed, early results from injection into Livermore's 2X-IIB mirror device with 30-keV beams off-axis are encouragingly close to achieving reversal [7].…”