Collisional instability in a rare magnetized plasma: an experimental model for magnetospheric and space plasma study

Abstract

AbstractIn a suitable experimental device, laboratory plasma is produced with conditions and parameters analogous to magnetospheric plasma; we light a rare plasma in a semi-machine using rf-frequency discharge. Three ranges of low-frequency instabilities appear, one of which is identified as drift, caused by electron–neutral collisions. A full theoretical elaboration adapted to production conditions and geometrical symmetry is carried out; one solution of the dispersion relation is sufficient justification for the existence of the instability. The mathematical analysis also has the ambition to give interpretation for other low-frequency waves. Here we make a sound identification of the instability type as drift resistive due to electron–neutral collisions by an investigation of the growth rate. An agreement between experimental results and the theoretical model is obtained. As in the magnetosphere, an external magnetic field restrains the plasma.