P. Bayetti, F. Bottiglioni, H. Dougnac, J.L. Farjon, W. Hess, M. Hesse, Ph. Lotte, W. Mandl, P. Monier-Garbet.
Association EURATOM-CEA, Departement de Recherches sur la Fusion Controlee,
Centre de Cadarache
13108 Saint Paul lez Durance Cedex, France
Interactions between neutral beams and plasmas are used to measure plasma characteristics. In TORE-SUPRA two beams are used to infer Ti(r), ni(r), Zeff(r), and plasma current profiles J(r). These diagnostics are entering into operation.
Ion temperature, density and impurities profiles measurements rely on an hydrogen modulated beam, produced by an injector called 'Source Module' (15 A - 50 kV - 100 Hz):
- Ion temperature and density profiles are obtained by measuring energy and mass of fast neutrals issued from the charge exchange between the beam and the ions of the plasma.
- Spectroscopic measurements (u.v. and visible) of the emission of the plasma impurities (C, O & B), excited by the beam, lead to ion temperature profiles and Zeff determination. On line measurements of beam species mix, and beam energy injected into the tokamak, which are necessary to calibrate the previous measurements, are presented.
Plasma current profiles are deduced from the Motional Stark Effect, on the D( or H( lines emitted by the excited beam atoms, issued from one out of the four injectors of TORE-SUPRA (20 A - 70 kV in H2 and 20 A - 80 kV in D2). The local ratio Bpoloidal / Btoroidal, and therefore the current profile, are inferred from the measurement of the polarization angle of the split lines. Beam characteristics are not available on line. Beam profiles, divergence, species mix and injector power inventory, measured on the test bed BEL, are presented.
A short discussion of both the involved physical processes and the beams requirements are presented, so as a technical description of the injectors.
First measurements of plasma characteristics are given.