Measurement of lower hybrid-driven current profile by Abel inversion of electron-cyclotron wave transmission spectra
A method for measuring the radial profile of the lower hybrid-driven current in a low density tokamak plasma using electron-cyclotron wave attenuation is discussed. This diagnostic scheme resembles the transmission interferometry approach, commonly used in tokamaks to measure the plasma density, but now the wave amplitude instead of the phase is measured. Wave attenuation of the ordinary mode at w(p) much less than w less than w(c) along vertical chords is measured. At these frequencies the waves are absorbed by the superthermal tail sustained by the lower hybrid waves, and the local wave absorption coefficient is proportional to the non-inductive current density. The radial profile of this current is obtained from the Abel inversion. An application to the Tore Supra tokamak is presented.
Bibliographic Reference: Report: EUR-CEA-FC-1417 EN (1991)
Availability: Available from CEA, Département de Recherches sur la Fusion Contrôlée, Saint-Paul-lez-Durance (FR)
Record Number: 199110504 / Last updated on: 1994-12-02
Original language: en
Available languages: en