On the necessary modifications 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 most important manifestation proves to be nonlinear convective penetration of field (current) into the plasma of Z-pinch. 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 possibility of numerical modelling of processes that involve the effects of EMHD on the basis of reliable, simple and well-operating MHD codes.