Dust in the Planetary System : Dust Interactions in Space Plasmas of the Solar System

Cosmic dust particles are small solid objects observed in the solar planetary system and in many astronomical objects like the surrounding of stars, the interstellar and even the intergalactic medium. In the solar system the dust is best observed and most often found within the region of the orbits of terrestrial planets where the dust interactions and dynamics are observed directly from spacecraft. Dust is observed in space near Earth and also enters the atmosphere of the Earth where it takes part in physical and chemical processes. Hence space offers a laboratory to study dust plasma interactions and dust dynamics. A recent example is the observation of nanodust of sizes smaller than 10 nm. We outline the theoretical considerations on which our knowledge of dust electric charges in space plasmas are founded. We discuss the dynamics of the dust particles and show how the small charged particles are accelerated by the solar wind that carries a magnetic field. Finally, as examples for the space observation of cosmic dust interactions, we describe the first detection of fast nanodust in the solar wind near Earth orbit and the first bi-static observations of PMSE, the radar echoes that are observed in the Earth ionosphere in the presence of charged dust