Interstellar hydrogen distribution in the heliosphere: what can be deduced from direct and remote measurements

Abstract:

In this work we present updated results of the analysis of available data concerning to distribution of the interstellar hydrogen atoms inside the heliosphere. Namely, we focus ourselves on two datasets: direct measurements of the ISN H fluxes by IBEX-Lo instrument in 2009-2018 and measurements of the backscattered Lyman-alpha radiation by SOHO/SWAN. We use state of art numerical model of hydrogen distribution in the heliosphere to calculate both the ISN H fluxes and the intensities of the backscattered Lyman-alpha heliospheric glow. Comparison of the model results with the data allows to derive information about the interstellar hydrogen far away from the Sun. We combine two different kinds of diagnostic (direct and remote measurements) to understand are they consistent with each other, and what else do we need to measure in order to resolve the existing problems.