Loading...
Publication
Plasmas generated by ultra-violet light rather than electron impact
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 1.8 MB | Adobe PDF |
Advisor(s)
Abstract(s)
We analyze, in both plane and cylindrical geometries, a collisionless plasma
consisting of an inner region where generation occurs by UV illumination, and
an un-illuminated outer region with no generation. Ions generated in the inner
region flow outwards through the outer region and into a wall. We solve for
this system's steady state, first in the quasi-neutral regime (where the Debye
length ${\lambda}_D$ vanishes and analytic solutions exist) and then in the
general case, which we solve numerically. In the general case a double layer
forms where the illuminated and un-illuminated regions meet, and an
approximately quasi-neutral plasma connects the double layer to the wall
sheath; in plane geometry the ions coast through the quasi-neutral section at
slightly more than the Bohm speed $c_s$. The system, although simple, therefore
has two novel features: a double layer that does not require counter-streaming
ions and electrons, and a quasi-neutral plasma where ions travel in straight
lines with at least the Bohm speed. We close with a pr\'{e}cis of our
asymptotic solutions of this system, and suggest how our theoretical
conclusions might be extended and tested in the laboratory.
Description
Keywords
Plasmas Ultra-violet light Electron impact . Faculdade de Ciências Exatas e da Engenharia
Citation
Franklin, R. N., Allen, J. E., Thomas, D. M., & Benilov, M. S. (2013). Plasmas generated by ultra-violet light rather than electron impact. Physics of Plasmas, 20(12), 123508. DOI: 10.1063/1.4848715
Publisher
American Institute of Physics