ON THE SINGLE-FLUID MODELING OF MASS-LOADED PLASMA

A modification of the single-fluid MHD approach for modeling a mass-lo aded plasma is proposed. The well known source terms in the single-flu id equations remain unchanged in the model. The finite time-duration o f the new ions assimilation is taken into account via introduction of additional currents and charges, considered as external to the basic f luid substance. These external currents and charges are caused by non- picked up new ions in the frame of time and length scales, smaller tha n the infinitesimal scales of the considered continuum. Possible quasi -quantitative estimates for so introduced parameters, based on additio nal knowledge of relaxation time, are considered. A kinematic analysis of the fluid and magnetic field lines reveals that the magnetic field is not frozen in. There are two velocity components of the obtained m agnetic held diffusion: diffusion component directed against the flow of the neutral particles, and pseudo-diffusion along the magnetic fiel d line. A generalization of the solution for solar wind flow past a co metary exosphere, containing two shocks and contact surface, is consid ered qualitatively in terms of this approach. Such a consideration pre dicts that the interplanetary magnetic field penetrates through the co ntact surface, reaching the inner shock, which becomes a diamagnetic b oundary.