Theory and Numerical Simulation of Collective Transport of Plasma in Magnetic Fields

摘要

Numerical and theoretical studies have been made on the transport of particles and heat in collisionless plasmas in magnetic fields for both quiescent and turbulent states. The following problems have been investigated:(1) A systematic kinetic theory of hydrodynamic fluctuations in a strong magnetic field has been developed to study the particle diffusion due to thermal convective cells. (2) Effects of density and temperature gradients on thermal convective cells;they are found to destabilize both the ion flute and the convective cells. (3) Effects of mirroring magnetic field on convective diffusion;they are found to increase the diffusion significantly even for open field lines of force. (4) Turbulent electron heat transfer due to short wavelength ion fluctuations near the lower hybrid frequency;this may be important in collisionless plasma. (5) Heat transfer due to emission and absorption of electrostatic plasma waves are studied theoretically and by simulation;agreement has been found for a strong magnetic field case. (6) Particle diffusion in a toroidal magnetic field due to collisions (neo-classical diffusion) and due to collective effects is studied by numerical simulations. Neoclassical theory agrees well with the numerical results when the long wavelength collective modes are suppressed.