The influence of the interface between the heliosphere and the local interstellar medium on the penetration of the H atoms to the solar system

A self-consistent gasdynamic model of the solar wind interaction with the local interstellar medium (LISM), which takes into account the mutual influence of the plasma component (electrons and protons) of LISM and the LISM H atoms that penetrate into the heliosphere, was constructed by Baranov et al. in the approximation of axial symmetry. This model, however, has a number of defects. In particular, the motion of the H atoms was described by the hydrodynamical equations, although the mean free path of the H atoms and the characteristic length of the problem are comparable. In this paper, the first step of an iterative method using Monte Carlo simulation is realized. To illustrate the effect of the plasma component of the LISM on the penetration of H atoms into the heliosphere, we calculate the trajectories of H atoms by the Monte Carlo method using the plasma parameter distributions obtained by the model of Baranov et al. for a fully ionized gas. The bulk velocity and the number density of H atoms as functions of the distance from the Sun for different values of polar angle are analyzed. The spatial distributions of the scattered solar Ly-alpha radiation for different values of LISM parameters are calculated and then compared with the observations of Prognoz 6 (Bertaux et al.). It is shown that the effect of the LISM plasma component on the penetration of H atoms into the heliosphere can give rise to reinterpretation of data on the scattered solar Ly-alpha radiation, if the degree of ionization of the LISM is sufficiently large.