Dust vortices, clouds, and jets in nuclear-induced plasmas

The collective movement of dust particles in a plasma formed during deceler ation of decay products of californium nuclei in neon is investigated exper imentally. For the first time, compact vortex structures containing a large number of coagulating dust particles and dense dust clouds evolving in tim e are observed. Dust formations have clearly defined boundaries and particl es in them form ordered liquid-type structures. Under steady-state conditio ns, dust structures exist from several minutes to hours. An increase in the voltage applied to the high-voltage electrode leads to the formation of du st particle jets. A change in the electric field configuration transforms t he structures from one type to another. A strong recombination of electrons and ions at dust particles is observed. The momentum transfer from ions dr ifting in an external field to gas molecules is studied using the Monte Car lo method. It is shown that the transferred momentum is so large that it ma y cause a gas flow. The characteristic features of vortex flow in neon and in air are explained. (C) 2001 MAIK "Nauka/Interperiodica".