Charge neutralization of dust particles in a plasma with negative ions

摘要

Charging of dust grains in a plasma with negative ions is studied experimentally. When the relatively mobile electrons are attached to heavy negative ions, their tendency to charge the grains negatively is reduced. In a plasma in which a substantial fraction of the electrons are eliminated (positive ionegative ion plasma), the grain charge can be reduced in magnitude nearly to zero ("decharging" or charge neutralization). If the positive ions are lighter than the negative ions, dust grains having a small net positive charge can be produced.