Plasma potential measurement using centre tapped emissive probe (CTEP) in laboratory plasma

Plasma potential measurements using a compensated center tapped emissive probe (CTEP) in quiescent plasma ($n_{\text{e}}\sim 6.0\times {10}^{11}\text{c}{\text{m}}^{-3},T_{\text{e}}\sim 3.5\text{eV}$) of large volume plasma device (LVPD) are presented. The CTEP shows distinct advantage over conventional emissive probe (CEP) because of measurement capability, independent of electronics and operating conditions of CEP. Its ability of measuring continuous, uninterrupted plasma potential (DC and fluctuations) measurements for pulsed and DC plasma discharges gives it advantage over other configurations. Also, its push fit design allows easy replacement without realizing frequent vacuum breaks. In small sized plasma devices, CTEP design may introduce some spatial resolution error but for large plasma devices, this is negligible as voluminous data is required over large scale lengths (∼few tens of cm). (paper)