ECRH resonance position measurement in TCV
A precise knowledge of the magnetic field is imperative for electron cyclotron resonance heating (ECRH) experiments in order to situate the position of the cyclotron resonance with respect to the magnetic surfaces. Between 20 kW 40 kW of first harmonic 40.3 GHz gyrotron radiation was injected into the vessel pre-filled with neutral deuterium with only the toroidal magnetic field coils energized. A 128 channel vertical multichannel D(alpha) camera measured the spatial distribution of the light emission with major radius together with a 9 channel horizontal D(alpha) camera to measure the vertical extent of the emitting region. The main cyclotron and upper hybrid resonance locations were measured for nominal magnetic fields in the range of 1.1 T to 1.47 T and compared to the field deduced from the magnetic pickup coils. A correction to the nominal value of approximately -2% was determined which corresponds to approximately 1.7 cm at the full field resonance position. The effect of this displacement is shown for a series of experiments in which 500 kW of second harmonic 80.2 GHz power was injected into a plasma with kappa approximately 1.3, across the region of the rational q = 1 surface.
Bibliographic Reference: Article: Bulletin of the American Physical Society, Vol. 42 (1997) No. 10, p.1858
Record Number: 199810136 / Last updated on: 1998-02-12
Original language: en
Available languages: en