Determination of fluctuations of the electron temperature and density in an ionizationunstable inert-gas plasma in a magnetogasdynamic channel

Abstract

Electron temperature and density fluctuations arising as a result of the development of ionization instability in nonequilibrium magnetogasdynamic channels, where a pure inert gas without alkali-metal seeding is used as the working gas, are studied in greater detail. An experiment was performed in a disk-shaped Hall-type magnetogasdynamic channel combined with a shock tube, with magnetic inductions greater than the inductance B c=0.57 T at which ionization inhomogeneities first appear in the experiment. The electron temperature and density were measured from the drop in the intensity of the continuous radiation in the UV region according to the Unsold-Kramers and Biberman-Norman theories. On the average, the electron temperature in inhomogeneities varies from 7000 to 10000 K and reaches its highest values in small-scale fluctuations. As a result of the absence of ionization equilibrium in the inhomogeneities, relatively small fluctuations of n e and a phase shift between the fluctuations of n e and T e are observed. At the same time, the average values of the electron density increase with the degree of supercriticality of the magnetic field. This evidently results in a higher effective conductivity.