Measurement of cold electrons in a pulsed inductively coupled plasma
Abstract
During the afterglow of a low pressure pulsed plasma, energetic electrons are rapidly lost to the walls while low energy electrons remain trapped within the ambipolar potential well, resulting in the fast cooling of the electron ensemble. In time, a collapse of the ambipolar potential occurs which depletes the electron energy distribution function in the high-energy range. Late in the afterglow, elastic electron-atom collisions are the only electron heating mechanism remaining. For a gas with poor thermal contact between gas atoms and electrons, diffusive cooling can cool electrons to temperatures around the gas temperature, and, in principle, even below that. We report direct measurements of cold electrons in the late afterglow that have been performed using a cylindrical Langmuir probe. The Laframboise model^1 has been employed to determine the electron temperatures. This work is supported by DOE under grant No. ER-54554. ^1 J. Laframboise, Theory of cylindrical and spherical Langmuir probes in a collisionless plasma at rest, in: Rarefied Gas Dynamics: P. 4th Int. Symp. Toronto/Canada 1964, vol.2, 22-43.
- Publication:
-
APS Annual Gaseous Electronics Meeting Abstracts
- Pub Date:
- October 2003
- Bibcode:
- 2003APS..GECET2003H