Electron cyclotron resonance heating (ECRH) is the main heating mechanism in the Wendelstein 7-X stellarator (W7-X). W7-X is equipped with five absolutely calibrated sniffer probes that are installed in each of the five modules of the device. The sniffer probes monitor energy flux of unabsorbed ECRH radiation in the device and interlocks are fed with the sniffer probe signals. The stray radiation level in the device changes significantly during the start-up phase: Plasma is a strong microwave absorber and during its formation the stray radiation level in sniffer probes reduces by more than 95%. In this paper, we discuss the influence of neutral gas pressure and gyrotron power on plasma breakdown processes.
|Number of pages||4|
|Journal||EPJ Web of Conferences|
|Publication status||Published - 24 Jul 2017|
|Event||19th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, EC 2016 - Gandhinagar, Gujarat, India|
Duration: 4 Apr 2016 → 7 Apr 2016