On the necessary modification of Z-pinch MHD-models

Numerical modelling of fast Z-pinch dynamics which allows for effects of electron magnetohydrodynamics (EMHD) is discussed; of these, the nonlinear convective penetration of field (current) into the plasma of Z-pinch is the most important manifestation. This highly nontrivial dynamics can be modeled using a relatively simple modification of the diffusion equation for magnetic field. Two models of this type are suggested - for a one-scale pinch and for a thin liner. As a consequence, this opens up the possibility of numerical modelling of processes that involve the effects of EMHD on the basis of reliable, simple and well-operating MHD codes. (author). 11 refs