Selection effects on interstellar dust in heliosphere Original Research Article

Detailed studies of the selection effects at work on interstellar dust grains during their entry into the heliosphere are important deducing the conditions of grains in the very local interstellar medium. In particular we study the influence of Lorentz and radiation pressure forces on the interstellar dust flux. Lorentz forces acting on grains selectively deplete smaller sized grains from their original flow near the heliopause and in the heliosphere, irrespective of dust composition. If interstellar grains in the very local interstellar medium are composite fluffy agglomerates as proposed for grains in the diffuse interstellar medium, then the radiation pressure force is sufficiently small that the size distribution and material composition can be retrieved from in situ measurements in the solar system. Although grains that consist only of silicate are scarcely influenced by radiation pressure, the flux of bare graphite grains is expected to decrease by radiation pressure in contrast to the constant flux derived from in situ measurements of grains in the heliosphere. It is unlikely that interstellar grains are destroyed by field emission or sputtering, even though the grains pass through shocks to enter the heliosphere, and by mutual collisions or collisions with interplanetary dust particles.