Electromagnetic Control of a Nonequilibrium Plasma Jet Impinging on a Flat Plate.

Abstract

Electromagnetic control of characteristics of a low-pressure plasma jet impinging on a flat plate in a pipe is experimentally investigated. The electron density and the electron temperature are measured by Langmuir probe. The heat flux is measured by a cylindrical heat flux probe. The response of plasma current to the bias electric field on a flat plate is measured by an electric probe similar to the Langmuir probe type. An impinging plasma jet near the flat plate area is visualized by means of CCD camera and a thermo-image processor. The distributions of the relative temperature on the flat plate are visualized by means of the interference fringes of chrome oxide on the stainless steel. It is shown that the electron density decreases close to the flat plate in both cases with and without a magnetic field. The region of Maximum electron temperature approaches the flat plate upon application of a magnetic field. The excited atomic temperature distributions show the same tendency as the electron temperature distributions. These characteristics occur due to the active recombination between ions and electrons near the plate and further wall recombination. The response of plasma current is more sensitive to the positive bias under the magnetic field. The relative temperature distributions clearly show that the plasma jet is stabilized by a magnetic field. These findings imply that an impinging plasma jet can be controlled effectively by applying magnetic field.