Experiments concerning the influence of grain magnetization on preplanetary dust aggregation

Coagulation of small dust grains is considered the basic mechanism forming planetesimals and cometesimals in a protoplanetary disk environment. Up to now, mainly mechanical and electrostatic interactions were treated. However, there is evidence that magnetic interactions between permanently magnetized dust grains could have played an important role in this aggregation scenario. Long-range magnetic forces are expected to accelerate the grain growth process, to align the constituents of the resulting aggregates, and to form chain-like structures of low fractal dimension D-f. We performed coagulation experiments in a dilute gaseous environment using micron-sized magnetized dust samples. We observed rapid growth of chain-like aggregates with very low fractal dimension D-f = 1.2. Implications for grain growth in the protoplanetary disk and future perspectives of the experimental work are discussed. (C) 2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.