Visible light emission of fusion plasmas can be observed in a narrow region close to the boundary on the confined region, where the density and temperature are both favorable for the emission of visible line radiation of Hydrogen, the main plasma material. This light emitting narrow region is also called radiating belt. The radiating belt characterizes the actual 'size' of the plasma - an important parameter also influencing fusion performance, hence the measurement of this attribute is of reactor-relevant importance.
In recent years the radiating belt was investigated in several fusion experiments. In Wendelstein 7-X (W7-X), the world's largest stellarator and most complex fusion device, even the magnetic configuration can be detected by observing the shape of the radiating belt. To be able to evaluate the experiments correctly, the size of the plasma, that is, the radiating belt, has to be determined with good time resolution (10 ms).
This is achieved by monitoring the visible plasma radiation by a special camera EDICAM (Event Detection Intelligent Camera), developed especially for the use at fusion experiments. Among others, EDICAM can tolerate magnetic fields up to 3 T and ionizing radiation to a level experienced at middle-sized fusion devices. EDICAM also features multiple region-of-interest (ROI) readout, allowing the simultaneous recording of small, fast (e.g. 256x64 @ 5 kHz) and large, slow (1280x1024 @ 100 Hz) regions. This feature allows us to monitor the radiating belt (large, slow ROI), and additionally to study faster phenomena such as plasma breakdown or pellet injection.
In late 2020 a new fusion experiment, the large superconducting tokamak JT-60SA is starting operation for the first time in Naka, Japan. An EDICAM system was installed at JT-60SA as well for monitoring the radiating belt - and all other phenomena observable in the visible range. The successful candidate would be responsible for the investigations of the radiating belt in JT-60SA. The studies would involve the comparison of the features of the radiating belt between stellarator and tokamak plasmas. Most of the new experiments would be carried out on the JT-60SA tokamak, and the young scientist would perform the evaluation and interpretation of the results for both W7-X and JT-60SA data. In case of interest participation in experiments as diagnostic operator is also possible in Japan or Germany.
As the experiments are in Europe and Asia strong collaboration is necessary with foreign laboratories. Good English language skills are required. The ability and self-interest to handle scientific equipment is also advantageous.