Thermal excitation of modes in a non-neutral plasma
- Creators
- Gould, Roy W.
Abstract
We examine theoretically the thermal fluctuations in a non-neutral plasma, as observed on a segmented electrode surrounding the plasma, using the Nyquist theorem. The fluctuation spectrum is peaked at frequencies which correspond to modes of the plasma. Measurement of these fluctuations and of the input admittance of the plasma in the vicinity of one of the mode resonances can be used to give a completely experimental, and non-destructive, measurement of the plasma temperature. Since some of the modes are negative energy modes and exhibit negative absorption due to the plasma rotation, a direct application of the Nyquist theorems will not give correct results for the non-axisymmetric modes. This problem is circumvented by first calculating the fluctuations in a frame rotating with the plasma and transforming to the laboratory frame. This results in a modification of Nyquist's theorem. Measurement issues are discussed.
Additional Information
© 2002 American Institute of Physics. The author is grateful to F. Anderegg for communicating the experimental results and to members of the U.C.S.D group for stimulating discussions.Attached Files
Published - GOUaipcp02.pdf
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Additional details
- Eprint ID
- 1809
- Resolver ID
- CaltechAUTHORS:GOUaipcp02
- Created
-
2006-02-19Created from EPrint's datestamp field
- Updated
-
2023-05-19Created from EPrint's last_modified field
- Series Name
- American Institute of Physics Conference Proceedings
- Series Volume or Issue Number
- 606