Letter to the Editor

Momentum transfer to interplanetary dust from the solar wind

¹ Department of Earth and Planetary Sciences, Nagoya University, Nagoya 464–8604, Japan e-mail: minato@eps.nagoya-u.ac.jp
² Institute of Low Temperature Science, Hokkaido University, Sapporo 060–0819, Japan
³ Institut für Planetologie, Westfälische Wilhelms-Universität, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany

Received: 7 May 2004
Accepted: 14 July 2004

Abstract

Solar-wind particles striking dust grains in orbit around the sun exert not only a repulsive force on the grains, but also a drag force, called the plasma or pseudo Poynting-Robertson (PR) effect, which limits their dynamical lifetimes. To better understand the dynamical evolution of interplanetary dust, we study the momentum transfer from the solar wind to interplanetary dust taking into account the passage of impinging particles through the grains. The pseudo PR drag is one of the most important perturbations for the dynamics of interplanetary dust of any sizes. However, previous studies underestimated the lifetimes of small grains by overestimating the acting solar-wind forces. Our study also provides the velocity distribution of neutralized solar-wind particles after passage through a grain along with some implications for the generation of pick-up ions by solar-wind interaction with dust grains.