Dust particle growth instabilities: amplitude evolution and Laser Induced Fluorescence investigations
Résumé
Dust particles in a plasma acquire a negative charge by attaching free electrons. The charge is proportional to the dust particle radius and when the global charge represented by the whole dust cloud becomes no more negligible with respect to the ion density, the plasma equilibrium is strongly disturbed. It can lead to the occurrence of instabilities that are easily observed on all discharge and plasma diagnostics. This phenomenon is relatively common in dust forming plasmas where a huge density of dust particles can be grown. We show that the evolution of the instability amplitude follows well-defined patterns related to different instability regimes. We also show preliminary results obtained using Laser Induced Fluorescence during these instabilities. It appears that the fluorescence signal amplitude increases during dust particle growth.