Aachen PK 2003 – wissenschaftliches Programm

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P: Plasmaphysik

P 4: Poster I

P 4.17: Poster

Montag, 17. März 2003, 17:45–19:15, Foyer

ECRH power deposition profile in ASDEX Upgrade — •Krassimir Kirov, Fritz Leuterer, Francois Ryter, and ASDEX Upgrade Team — Institut fuer Plasmaphysik, 85748 Garching

Electron cyclotron heating in ASDEX Upgrade is designed for very localised power deposition, even for the case of off-axis deposition by launching with a large poloidal angle. Experiment- ally we can determine the rate of change of the electron tempera- ture,dTe/dt, measured by ECE at many radial positions with a fast response time, when the ECRH power is switched on or off. Similarly, we can determine the radial profile of the temperature modulation in cases with modulated ECRH. However, these measure- ments cannot be taken in the immediate absorption zone, but only remotely on the same flux surface. Since the distribution of energy over the flux surface needs some time, the measured dTe profiles will be broadened due to diffusion. We use the ASTRA transport code to fit calculated dTe profiles to the measured ones in order to obtain effective deposition profiles. In the same way modulated temperature profiles are fitted to calculated ones.The thus obtained effective deposition profiles are 1.5 to 2 times broader than those calculated by the TORBEAM code, which assumes infinitely fast distribution of the energy over the flux surface.