Effect of Magnetic Field on Turbulence of Nonequilibrium Plasma Jet in Pipe.

Abstract

This paper clarifies experimentally the effect of magnetic fields on the turbulent structures of a nonequilibrium plasma jet in a pipe. Regarding the microbehaviors of electrons and ions measured by a probe method, the turbulence intensity of charged particles increases rapidly in the core region of a plasma jet in the applied magnetic field. The power spectrum of electron saturation current increases rapidly with the magnetic field and shows the same tendency as the power spectrum of ions. The power laws of -5/3 and of -13/3 indices can be observed in the power spectra of charged particles in the applied magnetic field. These imply strong coupling between electrons and ions. Visualizing macrobehaviors of a plasma jet in the applied magnetic field, an increase of deviations of the high-temperature region and a decrease of fluctuations of a plasma jet's center axis are observed using an infrared thermoimage processor. The increment of electron density of a plasma jet is also observed with a Mach-Zehnder interferometer. These results imply that enhancement and suppression of turbulence of a nonequilibrium plasma jet are possible using magnetic fields.