title: A comparative study of sheath potential profile measurements with laser-heated and current-heated emissive probes.
abstract: Emissive Langmuir probe is one of the most efficient diagnostic tools available for plasma potential measurements. Extensive studies have been carried out in designing different kinds of conventional (electrically heated) emissive probes (CEPs) to estimate the plasma potential. Laser heated emissive probe (LHEP) has been developed with certain advantages over the conventional probes such as low evaporation rate of the probe material, high lifetime, and high emission levels. Most importantly, the LHEP uses laser to heat the probe-tip and does not require electric current to heat the probe-tip like in CEP. The heating current in CEP substantially affects the plasma potential measurements, especially in the regions of plasma where high electric and magnetic field gradients are present. In this paper, we studied the plasma potential structures in sheath-presheath region using both LHEP and CEP in an unmagnetized dc-filament discharge plasma. Measurements of sheath spatial potential profile using laser heated emissive probe are compared with those obtained using conventional emissive probe.
authors.affiliation: Institute for Plasma Research, Bhat, Gandhinagar 382428, India.
authors.forename: Vara Prasad
authors.initials: VP
authors.lastname: Kella
authors.affiliation: Institute for Plasma Research, Bhat, Gandhinagar 382428, India.
authors.forename: Payal
authors.initials: P
authors.lastname: Mehta
authors.affiliation: VIT University Chennai Campus, Kelambakkam Road, Vandalur, Chennai 600127, India.
authors.forename: A
authors.initials: A
authors.lastname: Sarma
authors.affiliation: Institute for Plasma Research, Bhat, Gandhinagar 382428, India.
authors.forename: J
authors.initials: J
authors.lastname: Ghosh
authors.affiliation: Institute for Plasma Research, Bhat, Gandhinagar 382428, India.
authors.forename: P K
authors.initials: PK
authors.lastname: Chattopadhyay