Variations of interstellar H atom parameters in the outer heliosphere: solar cycle effects Original Research Article

In this paper, we study response of the heliospheric plasma interface, the region of the solar wind interaction with the local interstellar medium, to 11-year solar cycle variations of the solar wind. We explore how the solar wind variations influence interstellar H atoms in the heliospheric interface, which are coupled to plasma by charge exchange. We develop the self-consistent model, where the kinetic equation for interstellar H atom velocity distribution function is solved self-consistently with the gas dynamic equations for the charged (electrons and protons) component. It is shown that the termination shock location varies within ±7 AU, the heliopause variation is ∼2 AU, and the bow shock variation is negligible. The important new result is that at large heliocentric distances the density of the interstellar H atoms varies within ∼10% with solar cycle. The variation of density increases closer to the Sun up to 30% at 5 AU.