Nonlinear wave phenomena measured by capacitive probes during auxiliary heating in the SOL of TEXTOR
Measurements of different wave phenomena at the plasma boundary during auxiliary heating (ICRH and combined ICRH-NBI) experiments on TEXTOR were performed to elucidate some of the mechanisms responsible for ICRF-induced effects on the edge plasma and on plasma-wall interactions. Excited waves were studied during carbonised and boronised wall conditions in TEXTOR. Waves were detected at the r.f. generator frequency, and also at the harmonic frequencies due to sheath effects at the ICRF antenna. Furthermore, waves at half-harmonic frequencies were also excited under certain conditions. During carbonised machine operation conditions, waves at half-harmonic frequencies were always observed, except during the combined heating phase. Under normal boronised operation, no waves at half-harmonic frequencies were observed during neutral beam-ICRH combined heating of deuterium plasma. However, waves at half-harmonic frequencies were observed at higher toroidal magnetic field values, as well as during D neutral beam-ICRH combined heating at high H concentration and high r.f. power. Wave amplitudes at the different frequencies were studied as a function of different plasma and machine parameters.
Bibliographic Reference: Article: Plasma Physics and Controlled Fusion, Vol. 33 (1991) No. 10, pp. 1135-1144
Record Number: 199111659 / Last updated on: 1994-12-02
Original language: en
Available languages: en