An effect of neutral collisions on the excitation threshold of electrostatic ion-cyclotron waves
Abstract
Laboratory experiments using a sodium plasma are reported that demonstrate a robustness of electrostatic ion-cyclotron waves in the presence of elevated neutral-helium pressure. It is found that the excitation threshold decreases with neutral pressure, and that, in the presence of a transverse localized electric field, the waves are able to tolerate much higher collisionality than previously believed. When the ion-neutral collision frequency and ion gyrofrequency are comparable, the excitation threshold is significantly smaller than its collisionless value.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- August 1998
- DOI:
- 10.1029/98GL02331
- Bibcode:
- 1998GeoRL..25.3095K
- Keywords:
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- Ionosphere: Plasma waves and instabilities;
- Magnetospheric Physics: Plasma waves and instabilities;
- Space Plasma Physics: Laboratory studies;
- Planetology: Solar System Objects: Jovian satellites