Influence of magnetic field on plasma sheath and electron temperature

Abstract

Experimental observation has been carried out to see the effect of magnetic field and grid biasing voltage in controlling the sheath thickness in a magnetized plasma system. The experiment is carried out in a stainless steel chamber which is divided into two regions by a mesh grid, via the source region and the diffused region. The characteristic behavior of the ion rich sheath formed across the grid under various conditions of the applied magnetic field and grid biasing voltage has been investigated experimentally. It has been observed that at both conditions of increasing magnetic field and grid biasing voltage, sheath width expands in the source region, whereas in the diffused region, no such noticeable variation has been found. This study has been accompanied by the measurement of the electron temperature in both regions of the chamber via the source region and the diffused region with the help of the Langmuir probe. Plasma is produced in the source region and it penetrates into the diffused region through the grid. It has been found that the electron temperature decreases with increasing magnetic field in the source region while kept at a constant grid biasing voltage. However, in the diffused region the opposite variation has been observed. The variation of electron temperature with grid biasing voltage in both regions is not very significant.