Suprathermal electron transport studies in radio-frequency-heated tokamak plasmas

¹ CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
² Princeton Plasma Physics Laboratory, Princeton, NJ 08540, United States of America
³ École Polytechnique Fédérale de Lausanne (EPFL), Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland

^* Corresponding author: jean.cazabonne@cea.fr
^** See author list of B.P. Duval et al, Nuclear Fusion 64, 112023 (2024)
^*** See http://west.cea.fr/WESTteam

Published online: 7 January 2026

Abstract

This contribution reports on the study of suprathermal electron radial transport enhancement in the presence of electron-heating radio-frequency waves, such as electron-cyclotron waves or lower-hybrid waves. Since suprathermal electrons emit hard X-rays from Bremsstrahlung, experimental data from hard X-ray measurements are used to follow their dynamics. In particular, electron-cyclotron power modulation experiments performed in TCV show that this transport depends on the total electron-cyclotron power. These results are corroborated by experimentally constrained Fokker-Planck simulations [J. Cazabonne et al, Plasma Phys. Control. Fusion 65, 104001 (2023)]. Similar experiments have been performed in WEST with lower-hybrid waves, and are reported for the first time. Preliminary analyses show potential evidence of suprathermal electron transport, but no clear dependence on wave power nor photon energy at this stage.