Surface Temperature of Dust Particles in Plasmas Used for Microgravity Experiments

Microgravity experiments of dusty plasmas have been performed for a few decades on the International Space Station. The plasmas are generated by alternative current discharge. The dust particles are levitating in the plasmas for a few hours. Heating the dust particles and temperature on their surface are issues, since they are composed of a kind of resin and they must be kept chemically stable. The temperature on the surface of the dust particles were measured by observing fluorescence from a dye impregnated on the resin as the material of the dust particles. It was found to be stably held between 340 and 380 K in a range of plasma input power between 0.5 and 3.0 W. Conversely it was calculated in a model of heat exchange between the dust particles and thermal fluxes from ion and neutral species. Measured values and calculated ones were in good agreement. The surface temperature ensured that the resin as the material of the dust particles was not decomposed.