Neoclassical resonant plateau transport calculation in an effectively axisymmetrized tandem mirror with finite endplate resistance

Abstract

Calculations are made for neoclassical resonant plateau transport in the geometry of the effectively axisymmetrized tandem mirror GAMMA 10 magnetic field, which has minimum B inboard anchors inside the axisymmetric plug/barrier mirror cells. Azimuthal drifts in the local, non-axisymmetric regions are included. The radial potential profile is determined by solving the charge neutrality equation self-consistently. A finite resistance connecting the end plate to the machine ground provides appropriate boundary conditions on the radial electrostatic potential distribution so that it can be determined uniquely. The calculation is consistent with experimental results of GAMMA 10.

Flute instability and the associated radial transport in the tandem mirror with a divertor mirror cell

“…8 The nonaxisymmetric electrostatic potential in the central cell, which is formed artificially by the electron cyclotron resonance heating, can also enhance the large ion radial transport 9 as well as the neoclassical transport due to the nonaxisymmetric magnetic field. [10][11][12][13] Another operation is the one like a disruption observed in a big torus 14,15 or edge localized mode observed in a divertor tokamak, 16 where the plasma is made lost rapidly from the central cell. The rapid loss of plasma is realized with help of flute instabilities, which is one of the purpose of this paper.…”

Neoclassical resonant transport of a mirror cell

“…In this section we extend the neoclassical resonant transport theory [18][19][20][21][22][23] to calculate the ion radial flux in a nonaxisymmetric mirror. The diffusion coefficients are necessary to evaluate the particle loss attributed to the neoclassical resonant transport and some quantities of the particle motion are required in order to determine those coefficients.…”

“…The diffusion coefficient resulting from resonant ions trapped in the central cell is inserted in Fig. 7͑d͒ as a reference, 21 where the resonant ions pass from the mirror throat around z Ӎ −750 cm to another mirror throat around z Ӎ 750 cm in Fig. 1.…”

“…8͑d͒ as a reference. 21 It is found that D 0 decreases with T i due to the decrease of the population of resonant ions except for the central cell in Fig. 8͑d͒, where the population of resonant ions is proportional to The dependence of diffusion coefficients on the ion temperature of the anchor mirror cell and transition mirror cells is contrary for the case of the central mirror cell because the resonant energies ⑀ k in the anchor and transition mirror cells are much smaller than that in the central mirror cell.…”

“…9͑d͒ as a reference. 21 The ion radial confinement times resulting from resonant ions trapped in the anchor mirror cell ͓Fig. …”