Spontaneous formation of a transport barrier in helium plasma in a tokamak with circular configuration

0581965 - ÚFP 2024 RIV US eng J - Journal Article
Mácha, Petr - Adámek, Jiří - Seidl, Jakub - Stöckel, Jan - Svoboda, V. - Van Oost, G. - Lobko, L. - Krbec, Jaroslav
Spontaneous formation of a transport barrier in helium plasma in a tokamak with circular configuration.
Nuclear Fusion. Roč. 63, č. 10 (2023), č. článku 104003. ISSN 0029-5515. E-ISSN 1741-4326
R&D Projects: GA MŠMT(CZ) LM2023045
Institutional support: RVO:61389021
Keywords : ball-pen probe * golem * Langmuir probe * tokamak * transport barrier
OECD category: Fluids and plasma physics (including surface physics)
Impact factor: 3.3, year: 2022
Method of publishing: Open access
https://iopscience.iop.org/article/10.1088/1741-4326/acf1af

We report on the first experimental observation of a spontaneously formed transport barrier in the tokamak with a circular configuration in helium plasmas. There was no external polarization of the plasma by electric field or other technique to form the barrier as it is typically used in tokamaks with circular plasma. In general, the transport barriers play an important role in plasma confinement especially in tokamaks with divertor configuration. In our experiments, we clearly observe distinct characteristics of a transport barrier, including a steep gradient of the electron temperature and an enhanced radial electric field along with the change in the plasma potential, floating potential, and electron temperature fluctuation. The electron temperature and the plasma potential are obtained by a combination of the ball-pen and Langmuir probe measurements with high temporal resolution on a shot-to-shot basis. This first experimental observation of the spontaneously formed transport barrier might bring new possibilities to obtain a fusion-relevant study of the edge plasma parameters and transport in helium plasmas even on small tokamaks.
Permanent Link: https://hdl.handle.net/11104/0350105