Séminaire
The Solar system is surrounded by partially ionized Local Interstellar Medium (LISM). The solar wind interacts with the interstellar wind and as the result complex gasdynamical structure called the heliospheric interface is formed. Due to relative motion interstellar hydrogen atoms penetrate to the heliosphere, where they scatter the solar Lyman-alpha radiation. Interstellar hydrogen distribution in the heliosphere is very important source of information on both the local interstellar parameters and the heliospheric interface structure. Nowadays, an interest for investigations of the heliospheric boundary has increased due to unprecedented new data from Voyager-1 spacecraft, which probably crossed the heliopause in August, 2012.
During the seminar we will consider a state-of-art kinetic model of interstellar hydrogen distribution in the heliosphere. The model takes into account local temporal and heliolatitudinal variations of the solar wind and solar radiation as well as disturbances of hydrogen flow in the heliospheric interface due to charge exchange with protons. Obtained hydrogen distributions can be used for calculations of backscattered Lyman-alpha radiation in the Solar system. Some results of analysis of SOHO/SWAN and Voyager-1/UVS data on Lyman-alpha intensities will be presented.