New experiments on collisions of solid grains related to the preplanetary dust aggregation

The formation of planetesimals and cometesimals is due to inelastic collisions between dust grains and due to van der Waals and other attractive surface forces. These low-velocity collisions are believed to result from size-dependent friction with the dilute gas of the solar nebula. Any numerical simulation of the grain growth process must be based on assumptions about the collisional behaviour of these grains, which is a very complex theoretical problem. Therefore, we performed analogous laboratory experiments on individual grain-target collisions of micron-sized particles. We briefly summarize some important results, point out discrepancies to former work, and mention possible applications on solar nebula conditions with respect to the preplanetary dust aggregation, to a possible motion of charged particles due to magnetic forces, and to the formation of meteoritic chondrules due to 'lightning'. (C) 1999 COSPAR. Published by Elsevier Science Ltd.