∫° Plasma Confinement in a Levitated Magnetic Dipole
Plasma Physics Reports, Vol. 23, No. 9, 1997, pp. 742–750. From Fizika Plazmy, Vol. 23, No. 9, 1997, pp. 801–810. Original English Text Copyright © 1997 by Kesner, Mauel. MAGNETIC CONFINEMENT SYSTEMS Plasma Confinement in a Levitated Magnetic Dipole J. Kesner* and M. Mauel** * Massachusetts Institute of Technology, Cambridge, Ma 02129 ** Columbia University, New York, N.Y. 10027 Received April 1, 1995 Abstract—Plasma confinement in the field of a levitated dipole offers many advantages for magnetic fusion. MHD stability is obtained from compressibility which utilizes the large flux tube expansion of a dipole field. Such a device could be high beta, steady state, and exhibit good confinement properties. The large flux expan- sion will ease the difficulty of the divertor design. The configuration is ideal for electron cyclotron heating and controlled convective flow patterns may provide a mechanism for fueling and ash removal. 1. INTRODUCTION tribution function, µ is the adiabatic invariant, µ = The dipole magnetic field is the simplest and most e⊥/2B, J is the parallel invariant, J = °∫v || dl and the flux, common magnetic field configuration in the universe. It ψ is the third adiabatic invariant. The frequencies that is the magnetic far-field of a single, circular current Ω correspond to these invariants are respectively c the loop, and it represents the dominate structure of the cyclotron frequency, ω , the bounce frequency and ω middle magnetospheres of magnetized planets and neu- b d tron stars. The use of a dipole magnetic field generated the curvature driven precessional drift frequency. Both by a levitated ring to confine a hot plasma for fusion of these conditions lead to dipole pressure profiles that scale with radius as r–20/3 while the adiabatic distribu- power generation was first considered by Akira Haseg- µ awa after participating in the Voyager 2 encounter with tion function, F( , J) also implies a density dependence ∝ –4 ∝ –8/3 Uranus [1].
[Show full text]