Radial control of plasma uniformity and electron temperature by external plate biasing in a back diffused partially magnetized plasma

The possibility of achieving uniform and controllable plasma distribution remain a fundamental challenge in low pressure plasma discharges, which has numerous applications in plasma technologies. An external object when introduced in a magnetized plasma can significantly alter the spatial plasma distribution. In this paper, the effect of external plate biasing on both axial as well as radial characteristics of an expanding, partially magnetized plasma column, created by hot cathode filament inside a linear plasma device is presented. It is found that by applying a positive potential to a conducting external electrode, placed at a remote location away from the primary discharge region; the back diffused plasma tends to become uniform. The plate biasing also results in an overall increase in electron temperature of the expanding plasma; however, it does not appear to alter the radial plasma characteristics inside the source and the biasing region. A possible mechanism behind observing this effect has been provided.