Numerical simulation of axisymmetric, collisionless, finite-β plasma

Abstract

A numerical simulation method for time-dependent, axisymmetric, collisionless, finite-β plasma is described and applied to mirror modes in θ pinches and to rotational and tearing modes in Astron. It is shown that the mirror modes cause an increase of axial thermal velocities and the long time development of a gross bumpy structure in the θ-pinch plasma. The Astron plasma layer first develops tearing modes in agreement with linear theory, but at later times the wavelength of this mode increases by coalescence until the plasma is completely reassembled.