On the distribution function of H-atoms in the problem of the solar wind interaction with the local interstellar medium (LISM)

V.B. Baranov, V.V. Izmodenov, Yu.G. Malama
Institute for Problems in Mechanics, Russian Academy of Science, Prospect Vernadskogo 101, Moscow, 117526, Russia


The models of the solar wind interaction with the supersonic flow of the local interstellar medium (LISM) self- consistently taking into account mutual influence of plasma (electrons and protons) and neutral (H atoms) components of the LISM are analyzed. The flow of the neutral component cannot be described in the framework of hydrodynamical equations, because the mean free path of H atoms is comparable with the characteristic length of the problem (for example, with the size of the interface region). That is why Baranov and Malama (JGR,1993,v.98, N A9) constructed the model where only plasma component is described by hydrodynamical equations and the motion of H atoms is considered on the basis of kinetic approximation. Later Zank et al. (JGR, 1996, 101, N A10) used a multifluid model. The last model is based on the main assumption that the distribution functions of the all H atom populations are Maxwellian. On the basis of the model by Baranov and Malama [1993] we show here that the distribution functions of the all H atom populations are significantly not Maxwellian. The comparisons of the results obtained on the basis of the kinetic model by Baranov and Malama [1993] and multifluid model by Zank et al. [1996] show that the distributions of H atom parameters have large quantitative as well as qualitative distinctions. A number of theoretical predictions and relevant, experimental data are analyzed.

AGU Index Terms: 2124; 2144 Interstellar gas; 2151 Neutral particles; 7843 Numerical simulation studies
Keywords/Free Terms: heliosphere, solar wind, interstellar medium, interstellar atoms

JGR-Space 97JA03662
Vol. 103 , No. A5 , p. 9575

© 1998 AGU