Experimental investigation of particle heating in a strongly coupled dusty plasma
نویسندگان
چکیده
Highly charged dust particles in a plasma can be strongly coupled when their kinetic temperature is low. This temperature is determined by a balance of heating and gas cooling. The heating is believed to be electrostatic, although its exact nature is still under investigation. Experiments in a multiple-layer plasma crystal were conducted to test proposed heating mechanisms. A method for measuring small-amplitude, low-frequency fluctuations in ion density was developed and, using this, very low-frequency electrostatic fluctuations were found upstream of the particles. These fluctuations should propagate with the ions towards the particles and heat them. However, the fluctuations were uncorrelated with, and too weak to account for, the observed particle temperatures. In the experiment, the temperature increased and then decreased with gas pressure; this result is only partly consistent with an ion wake heating mechanism. These negative findings help narrow the range of possible explanations for the observed temperatures. © 2000 American Institute of Physics. @S1070-664X~00!01109-5#
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