High pressure radio frequency plasma in a pulsed magnetic field

Abstract

The high pressure plasma produced by an r.f. induction plasma torch has been investigated in a pulsed magnetic field using spectroscopy, high speed photography, inductive probes and a diamagnetic loop. Radiation and temperature of the plasma have been measured under various conditions of the torch and various intensities of the pulsed field. In most cases Joule-heating has been found the main mechanism of energy transfer to the plasma. From the decay of temperature in the plasma afterglow a value of radiative recombination in dense argon plasma has been found. Various properties of the torch in the absence of a pulsed magnetic field have also been investigated. These investigations cover gas breakdown at the torch initiation, measurements of the r.f. magnetic field in the plasma and the plasma instabilities. The measurements of the r.f. magnetic field provide information leading to estimates of plasma conductivity, electrical parameters and efficiency of the torch. The study of plasma instabilities reveals their sources and helps to suppress the acoustic noise from the torch.