Observatoire de Paris Institut national de recherche scientifique français Univerité Pierre et Marie Curie Université Paris Diderot - Paris 7

The heliosphere as a laboratory for cosmic dust research

Friday 28 May 2010, by Ingrid Mann (Institute for Space Aeronomie, Uccle, Belgium; School of Science and Engineering, Kinki University, Higashi-Osaka, Japan)

Wednesday 2 June 2010 à 14h30 , Lieu : Salle de confĂ©rence du bât. 17

Astrophysics and planetary science consider numerous dust phenomena, but most of them are derived from theoretical considerations. The dust of sizes of the order of several 10 nm and smaller, denoted as nano dust, evades most observations, since the cross sections for scattering and for thermal emission of a solid particle drop steeply in the size range that is maller than the considered wavelength. On the other, the nano dust, because of its large surface area relative to the small mass efficiently interacts with surrounding atoms, ions, molecules and radiation. Laboratory studies of nano dust are very limited, but show, for instance, that heating, sublimation, charging and alteration of the microstructure evolve differently for the nano dust than for larger particles. Space measurements allow utilizing the solar system as a laboratory. In-situ measurements show that the flux of interstellar dust that enters the solar system is modulated in the solar wind. Nano dust that forms within the solar system by fragmentation of larger objects is accelerated in the solar wind and crosses Earth orbit with speed of about 300 km/s. The recent measurements with STEREO near 1 AU and future in-situ measurements in the inner solar system provide an exciting new tool for studying cosmic dust and its interactions in a plasma.