Effect of cage bias and electron emission on the two-electron temperature groups in a hot cathode discharge

Abstract

In the target multi-pole magnetic cage of the double plasma device, where the plasma diffuses through the magnetic filter after its production in the source region, the effect of the cage biasing, introduction of auxiliary filament and accelerating voltage on the control of the temperature and density of the two-electron groups in a hydrogen bi-Maxwellian plasma is carried out. This control of the electron groups in turn will help to enhance the negative ion density. In the absence of biasing voltage, the density of low-energy electrons and high-energy electrons were of the orders ∼1014 m−3 and ∼1012 m−3 respectively. As the cage is biased negatively, these values increased to an order of ∼1016 m−3 and ∼1013 m−3 respectively. With negative cage biasing, the temperature of the high energy electrons was ∼5 eV and low energy electrons ∼0.6 eV. The introduction of an auxiliary electron source in the target region together with the application of an accelerating voltage along with biasing voltage further increased the density of low-energy electrons to ∼4 × 1016 m−3.