Measurement of current drive profile using electron cyclotron wave attenuation near the O-mode cut-off
A method for determining the radial profile of the lower-hybrid current drive in tokamaks using electron-cyclotron attenuation of the O-mode for frequencies near the cut-off frequency is discussed. For a given wave frequency, the cut-off plays the role of a spatial filter selecting a variable portion of the non-inductive current. It is shown that the incremental attenuation resulting from a small increase of frequency displays specific features related to the current density near the cut-off point. Using the relation between the wave damping and the current density, it is possible to determine the radial profile of the current drive from the wave attenuation measurements. A numerical application is also presented for plasma parameters in the reactor regime.
Bibliographic Reference: Report: EUR-CEA-FC-1413 EN (1991) 30 pp.
Availability: Available from CEA, Département de Recherches sur la Fusion Contrôlée, Saint-Paul-lez-Durance (FR)
Record Number: 199110518 / Last updated on: 1994-12-02
Original language: en
Available languages: en