Pulsed plasma guns are used to obtain high-velocity
(107–108 cm/s) plasma flows.
Their performance is restricted by an instability of the
plasma acceleration by a magnetic field. This paper presents
results of a 2D numerical study of plasma dynamics in the
plasma gun. The ZENIT-2D code solving the magnetohydrodynamic
(MHD) equations on a fixed Eulerian mesh is used. The plasma
parameters and geometry are chosen to be close to the parameters
of the MK-200 installation (Sidnev et al., 1983).
The influence of the initial distribution of a neutral
gas on accelerator performance is investigated. A brief
description of the code and details of the simulations
are presented. It is shown that the instability of acceleration
leads to turbulent mixing of the plasma and magnetic field
and, correspondingly, to a broader current channel than
that predicted by the classical diffusion with the Spitzer
conductivity. Numerical results are compared with experimental
data (Bakhtin & Zhitlukhin, 1998) displaying a good
qualitative agreement.