Void behavior and profile using Laser Induced Fluorescence
Résumé
A three-dimensional dust cloud trapped in a plasma is often characterized by a central dust-free region. This region, called void, is a place where the plasma characteristics are different from the rest of the plasma containing the dust particles. This particularity is easily observed by the naked-eye as the light emission is strongly enhanced in the void. In order to get information on the plasma properties inside the void, optical diagnostics have to be performed on this localized region. Laser Induced Fluorescence is an efficient method that can reveal the local gas temperature and neutral excitation. When the ions can be observed, information on local electric fields can be deduced. In this contribution we discuss some general characteristics of the void and show preliminary results obtained thanks to the LIF diagnostics.