Journal of Physical Studies 9(3), 268–271 (2005)
DOI: https://doi.org/10.30970/jps.09.268

ABOUT A STATIONARY PLASMA EXPANSION INTO VACUUM IN THE PRESENCE OF GRAVITATIONAL AND ELECTRIC FIELDS

V. M. Efimenko^{1}, V. V. Tokiy^{2}, N. V. Tokiy^{2}
^{1}Taras Shevchenko National University of Kyiv, Astronomical Observatory,
3 Observatorna Str., Kyiv, UA-04053, Ukraine,
e-mail: efim@observ.univ.kiev.ua,
^{2}A. A. Galkin Physic-Technical Institute of Donetsk NAS of Ukraine,
72 R. Luxemburg Str., Donetsk, UA-83114, Ukraine,
e-mail: nat1976@mnogo.ru

A classical solution for stationary spherically symmetric plasma expansion into vacuum taking into account both the gravitational and electric fields is examined. A system of four equations including continuity, ion motion, local electron equilibrium equations and equation of quasineutrality of stationary spherically symmetric plasma flux under homogeneous temperature of the components is presented. Considering boundary conditions, a set of dependences of the ion velocity and concentration, electric field and electron density on distance from the center of a plasma source is derived. The electric charge of the source of the stationary spherically symmetric plasma flux is assessed. The obtained results are applied to the solar wind and laboratory plasma. A significant discrepancy between the field direction and charge sign of the laboratory source and Sun is observed at the same boundary speed smaller than the critical one.

PACS number(s): 96.60.Pb