Interstellar dust distribution outside the heliopause: deflection at the heliospheric interface

Abstract

We developed a numerical model of the interstellar dust distribution in the global heliosphere including the heliospheric interface, where the solar wind plasma interacts with the local interstellar plasma. The model is based on the plasma distributions obtained by the 3D kinetic-magnetohydrodynamic model of the heliospheric interface developed by Izmodenov & Alexashov (2015). This paper explores how the dust particles with different initial charge-to-mass ratios (q_∞/m) are filtered and deflected in the outer heliosheath. It is shown that the Lorentz force caused by the interstellar magnetic field leads to formation of specific features of the distribution of dust especially in the case of intermediate gyroradius (∼several AU). We also study the characteristics of the dust flow at the entrance to the heliosphere. We show that more than 70 per cent of particles with q_∞/m ≤ 2 C kg^-1 penetrate to the heliosphere. At the nose part of the heliopause, these dust particles are decelerated up to 15 per cent and deflected from the interstellar wind direction by up to 35°. This deflection depends on polarity of the interstellar magnetic field. Distribution of particles with q_∞/m > 0.5 C kg^-1 upstream of the heliopause is not uniform and even not axisymmetric due to the assumed inclination of the interstellar magnetic field with respect to the interstellar wind direction.