Göttingen 2025 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 17: Poster Session II

P 17.41: Poster

Mittwoch, 2. April 2025, 16:15–18:15, ZHG Foyer 1. OG

ECRH Power deposition and Te perturbation investigations using dynamic ECE analysis — •Vaishnavi Murugesan, Matthias Hirsch, Gavin Weir, Juan Fernando Guerrero Arnaiz, Neha Chaudhary, and Robert Wolf — Max Planck Institute for Plasma Physics

At Wendelstein 7-X, the plasma electron temperature profile is derived by assuming that the Electron Cyclotron Emission (ECE) behaves like a blackbody radiation from a certain layer in the plasma. When the plasma is heated using Electron Cyclotron Resonance Heating (ECRH), the microwave beams are absorbed in a thin layer where they are in resonance with the gyration frequency of the electrons. When the ECRH beam power is modulated, perturbations in plasma temperature are initiated, that propagate away from the deposition zone. This modulation is observed as an immediate response in the ECE signals. The goal of this work is to study this zone of power deposition.

A first approach is to do a conditional averaging over the modulation periods and deriving a slope of the local dT/dt that allows the calculation of the power deposition profile. To study the temperature profile during these modulation events, the radiometers should sample at a rate that is at least twice the collision rate of the electrons during these events. For this, a high frequency-resolution radiometer backend called the ZOOM system, has been upgraded to help monitor the power deposition zones at high sampling rates.

Keywords: Electron Cyclotron Emission; Wendelstein 7- X; Power deposition; Electron Cyclotron Resonance Heating