Dust in the Interplanetary Medium

TL;DR

This paper reviews the properties, behavior, and detection of dust particles in the interplanetary medium, highlighting recent findings on nano dust trapping, ejection, and detection near 1 AU, and discussing their implications for solar wind interactions.

Contribution

It provides a comprehensive overview of interplanetary dust, including recent calculations and observations of nano dust dynamics and detection methods near Earth.

Findings

Nano dust particles are trapped near the Sun and ejected beyond 0.15 AU.

Fluxes of nano dust are detected near 1 AU using plasma wave instruments.

Dust impacts produce electric signals that are still under analysis.

Abstract

The mass density of dust particles that form from asteroids and comets in the interplanetary medium of the solar system is, near 1 AU, comparable to the mass density of the solar wind. It is mainly contained in particles of micrometer size and larger. Dust and larger objects are destroyed by collisions and sublimation and hence feed heavy ions into the solar wind and the solar corona. Small dust particles are present in large number and as a result of their large charge to mass ratio deflected by electromagnetic forces in the solar wind. For nano dust particles of sizes 1 - 10 nm, recent calculations show trapping near the Sun and outside from about 0.15 AU ejection with velocities close to solar wind velocity. The fluxes of ejected nano dust are detected near 1AU with the plasma wave instrument onboard the STEREO spacecraft. Though such electric signals have been observed during dust impacts before, the interpretation depends on several different parameters and data analysis is still in progress.