In order to understand plasma formation processes in a neutral loop discharge, measurements of population densities of excited levels of helium atoms were performed using laser induced fluorescence (LIF) spectroscopy. At the same time, profiles of electron density ne and electron temperature Te were measured using Thomson scattering. The results of these measurements were analyzed using a collisional-radiative model of helium atoms in the plasma. It was found that population densities of excited levels of the helium atoms were consistent with the values of ne and Te. This indicates that it is not necessary to consider an existence of a high energy electron component which may be supposed to theoretically exist in addition to the Maxwellian energy distribution function for the bulk of electrons at the measured temperature Te. Also, it was shown that the energy deposition to electrons in the vicinity of the neutral loop plays a essential role in the formation of the neutral loop discharge plasma.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)