Langmuir Probe Technique to Measure Variation of Plasma Parameters with Magnetic Field

The response of a probe with varying applied potential was studied at various operating pressures and the effect of magnetic field strength on the characteristics of argon plasma was investigated. Using a single Langmuir probe, the temperature and density of electrons were measured in both the presence and absence of a magnetic field. Sheath thickness was determined and the fluctuation of the density of ion current with working pressure was also examined. The results show that the electron temperature and sheath thickness vary inversely with the gas pressure and magnetic field strength, but the values of electron density increase with increasing pressure and magnetic field. In addition to that, when a magnetic field is applied, two groups of electrons are observed. Here, the values of the ion current density in the absence of magnetic field are greater than the ion current density in the presence of an applied magnetic field.