Positive charging of dust grains in an afterglow plasma

Dr. Neeraj Chaubey; Dept. of Physics and Astronomy, The University of Iowa

A positive charge on a grain is common in space plasmas, but uncommon in laboratory plasmas. Nevertheless, we found an experimental approach for charging grains positively, without photoemission. The grains are immersed in a plasma that has more ions than electrons, due to turning off the plasma source. In this non-neutral plasma, called an afterglow, the grain charges to a positive value that can be controlled by varying the ion energy.

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