Spectroscopic Investigation of Enhanced Plasma Oscillations in a High-Voltage Theta Pinch

Abstract

Intensity and frequency of fluctuating electric fields are obtained from a “plasma satellite” on the 21P ‐ 41D line of helium observed in the piston field of a collisionless shock. In contrast to second‐order perturbation theory only one satellite is seen. The perturbation theory is developed, therefore, to higher orders. Agreement between this theory and experiment is achieved. From the observed level of electric field fluctuations an effective collision frequency of about one‐fourth of the ion plasma frequency can be deduced.