Time -and Space-Resolved Measurement of Fluctuating Electric Field during a Theta-Pinch Implosion

Abstract

Time- and space-resolved observations of fluctuating electric fields are made using the plasma satellites of the HeI 492.2 nm line during art implosion phase in a small-linear theta pinch. The rapid excitation (up to ∼6 kV/cm) and decay of the fluctuating fields with the frequency smaller than the electron plasma frequency are observed except near the center of the plasma column. Measurement of the magnetic field B_z indicates that the intense fluctuating fields are localized in a narrow layer just behind the imploding magnetic front. From a measurement of the ion temperature, the fast ion heating and thermalization are observed in the implosion phase. These fast heating and thermalization and the decay of the fluctuations are almost coincident in time.