Comparative study of plasma parameters by using movable langmuir single and double probe in arc plasma

In this work, plasma is produced by arc discharge between two copper electrodes and is characterized by using a movable Langmuir probe. It is a simple way to measure plasma parameters such as electron temperature, electron density, ion density, Debye length, floating potential, etc. A movable Langmuir single probe technique has a reference point since it is biased with reference to one of the electrodes of the plasma producing system. In some situations such as radio frequency discharges, no reference point is available to bias the movable single probe. Hence, a single probe technique is not applicable and hence, the movable double probe technique is more appropriate. In this method, each probe is biased with respect to the other. The two probes in a vertical plane are biased with a potential and allowed to move through the arc plasma. Depending on the magnitude of biasing potential charges are collected by the probes and hence current flowing to the probe circuit is estimated. The plasma thus produced in laboratory has various applications which include gaseous discharge, plasma torch, sputtering, laser produced plasma as well as to Tokamak plasma.

Author: 
Ghanshyam Thakur, Raju Khanal and Bijoyendra Narayan
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