A steady-state tokamak reactor using the compressional Alfvén wave

Abstract

A tokamak reactor concept for steady-state operation has been studied. This reactor uses the compressional Alfvén wave to sustain the plasma current. Its structure is simplified by eliminating the poloidal coils in the torus centre. The start-up scenario is obtained by minimizing the wave and electric powers of the coils through solving the power balance and Grad-Shafranov equations. The steady-state operating point is obtained from the viewpoint of maximizing the Q-value (Q = fusion power/current drive power). The largest Q-value is obtained by using compressional Alfvén wave rather than other RF waves.

Advanced tokamak reactors based on the spherical torus (ATR/ST). Preliminary design considerations

“…Average Ni/Cu 64 Ni from « 3 Cu(n, Y ) 1.06(10)- 3 63 Ni from 63 Cu(n,p) 5.53(10)-« 60 Ni from 63 Cu(n,a) 1.26(10)" 7 62 Ni from 63 Cu(n,2n) 3.05(10)- 5 65 Ni from 65 Cu(n,2n) 8.14 (10)…”

Lower hybrid current drive in the presence of a DC electric field

“…The basic equations for analysis are the Boltzmann equation and Faraday's law. Since we focus on the ramp-up and recharge times, we restrict ourselves to the time-scale t > T Ee > V~Q 1 . We use a one-dimensional treatment of velocity parallel to the magnetic field (B t ), but a correction factor for the two-dimensional effect of velocity space is introduced since it is important for current drive.…”

“…Current drive by RF waves with regard to the operation of a tokamak reactor has been intensively studied [1][2][3]. These studies are restricted to the case where the DC electric field is neglected in the quasilinear theory of RF current drive while it is taken into account in the plasma circuit equation.…”

“…Most of these studies concentrated on current drive efficiency obtained from the steady solution of the Fokker-Planck equation. In the current ramp-up and recharge phases, the plasma parameters change with time, on the time-scale t > r £ e > VQ 1 , where r E e is the electron energy confinement time and v 0 is the electron collision frequency. It is possible to obtain the time dependence of plasma current and DC electric field through the plasma circuit equation.…”

Nonlinear interactions of two compressional hydromagnetic waves

“…But their nonlinear behaviour is not so extensively documented. The possibility of providing effective supplementary heating of a tokamak plasma through waves generated in the vicinity of the ion cyclotron frequency and its harmonics (Hooke & Hosea 1972;Hosea & Hooke 1973;Stix 1975;Ivanov & Kovan 1975;Hasegawa & Chen 1976;Hosea et al 1979;Rutherford 1980) and the steady-state tokamak reactor concept (Fisch & Karney 1981;Okazaki et al 1984) have made the study of the nonlinear behaviour of hydromagnetic waves very important. Most recent work on compressional hydromagnetic waves has been devoted to the study of various nonlinear damping processes, for example parametric decay (Cramer & Sy 1979), mode conversion (Amagishi, Trushima & Inutake 1982) and two-ion hybrid resonance (Swanson 1976;Perkins 1977;Jacquinot, McVey & Scharer 1977;Hosea et al 1979).…”