Wave focusing near the electron cyclotron frequency in hot plasmas
- Departement de Recherches sur la Fusion Controlee, Association Euratom-CEA, Centre d`Etudes de Cadarache, 13108 St. Paul-lez-Durance (France)
Microwave transmission spectra measured on the Tore Supra tokamak [Equipe Tore Supra, in {ital Proceedings} {ital of} {ital the} 12{ital th} {ital International} {ital Conference} {ital on} {ital Plasma} {ital Physics} {ital and} {ital Controlled} {ital Nuclear} {ital Fusion} {ital Research}, Nice, 1988 (International Atomic Energy Agency, Vienna, 1989), Vol. 1, p. 9] exhibit a systematic enhancement of the transmitted power at frequencies close to the electron gyrofrequency, often well beyond the corresponding level detected in vacuum. In order to explain such observations, the problem of electromagnetic wave propagation near the electron cyclotron frequency in a hot magnetized plasma is investigated in the framework of geometrical optics. The simple case of the ordinary mode injected vertically is studied by taking the finite plasma temperature and relativistic corrections to the dispersion relation into account, in contrast with the more familiar cold plasma ray-tracing approach. It is found that the ray trajectories are strongly affected by such effects in the anomalous dispersion region close to the cyclotron resonance. As a consequence of this analysis, it is shown that the local enhancement of the transmitted power observed experimentally can be explained as a focusing phenomenon related to hot-plasma corrections to the wave refractive index. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.
- OSTI ID:
- 165031
- Journal Information:
- Physics of Plasmas, Vol. 2, Issue 3; Other Information: PBD: Mar 1995
- Country of Publication:
- United States
- Language:
- English
Similar Records
O-regime dynamics and modeling in Tore Supra
Modulational excitation of drift waves by a beam of lower-hybrid waves