Observations of dusty plasmas with magnetized dust grains

We report a newly observed phenomenon in a dusty plasma device of the Q-mac hine type. At low plasma densities the time required by the plasma to retur n to its no-dust conditions, after the dust dispenser is turned off, can be as long as many tens of seconds or longer. A tentative interpretation of t his observation in terms of magnetized dust grains is advanced. It appears that an important loss mechanism of fine dust grains is by ion drag along t he magnetic field lines. The effect of ion drag is somewhat counteracted by the -mu delB force present when the magnetic field has a mirror geometry.