Speaker
Description
Energetic-particle observations of second harmonic tritium heating in JET DTE3 and comparison with H-minority heating
M.J. Mantsinen $^{1,2}$, P. Jacquet$^{3}$, D. Gallart$^{1}$, K. Kirov$^{3}$, E. Lerche$^{3,4}$, D. Taylor$^{3}$, C.D. Challis$^{3}$, E. Delabie$^{5}$, A. Kappatou$^{6}$, D. Keeling$^{3}$, D. King$^{3}$, V. Kiptily$^{3}$, M. Nocente$^{7,8}$, E. Parr$^{3}$, S. Silburn$^{3}$, E.R. Solano$^{9}$, Z. Stancar$^{3}$, E. Tsitrone$^{10}$, JET Contributors$^{11}$ and the EUROfusion Tokamak Exploitation Team$^{12}$
$^{1}$Barcelona Supercomputing Center, Barcelona, Spain
$^{2}$ICREA, Barcelona, Spain
$^{3}$United Kingdom Atomic Energy Authority, Culham Science Centre, Abingdon, Oxon, OX14 3DB, United Kingdom of Great Britain and Northern Ireland
$^{4}$Laboratory for Plasma Physics, ERM/KMS, B-1000 Brussels, Belgium
$^{5}$Oak Ridge National Laboratory, TN 37830 Oak Ridge, USA
$^{6}$Max-Planck-Institut für Plasmaphysik, Boltzmannstr. 2, 85748 Garching, Germany
$^{7}$Institute of Plasma Science and Technology, CNR, 20125 Milano, Italy
$^{8}$Dipartimento di Fisica ‘G. Occhialini’, Universit`a di Milano-Bicocca, Milano, Italy
$^{9}$Laboratorio Nacional de Fusión, CIEMAT, 28040 Madrid, Spain
$^{10}$CEA, IRFM, F-13108 St-Paul-Lez-Durance, France
$^{11}$See Maggi et al 2024 (https://doi.org/10.1088/1741-4326/ad3e16) for the JET contributors.
$^{12}$See Joffrin et al 2024 (https://doi.org/10.1088/1741-4326/ad2be4) for the EUROfusion Tokamak Exploitation Team.
Second harmonic ICRF heating of tritium is the reference ICRF heating scenario for ITER D–T plasmas. It has previously been investigated in D–T plasmas on TFTR [1-2] and JET [3-6], including high-performance JET plasmas during the second main D-T campaign (DTE2) at JET [7]. During the third main D–T campaign (DTE3) at JET, the scheme was revisited in H-mode plasmas and directly compared with hydrogen minority heating, which is an established ICRF heating scheme at JET with good heating performance.
Four DTE3 discharges, 104547–104550, were performed to investigate second harmonic tritium heating and to compare it with H-minority heating. The two heating scenarios were compared under similar plasma conditions with combined deuterium neutral beam injection and ICRF heating, allowing their heating performance and energetic-particle characteristics to be assessed. Neutral particle analyser measurements, neutron and gamma spectroscopy,lost fast ion diagnostics, and PION modelling are used to investigate the fast-ion populations and ICRF power partitioning. The two heating schemes produced similar ion temperatures, neutron rates and sawtooth-free periods, while the second harmonic tritium case resulted in lower electron temperature and stored plasma energy. Markedly different energetic-particle signatures were nevertheless observed as expected: clear energetic H and D fluxes were measured during H-minority heating, whereas no H, D or T fluxes above background were detected during second harmonic tritium heating.
The neutron spectra of the two second harmonic tritium discharges also show differences associated with plasma density, providing additional information on the underlying energetic-ion populations. PION modelling is used to investigate the role of intrinsic and the resulting partition of ICRF power between fast ions, bulk ions and electrons. The DTE3 measurements provide new experimental information on energetic-particle generation during second harmonic tritium heating and new benchmarks for modelling this ITER-relevant ICRF scenario.
References
[1] Phillips C.K. et al 1995 Phys. Plasmas 2 2427
[2] McGuire K.M. et al 1995 Phys. Plasmas 2 2176
[3] Start D.F.H. et al 1998 Phys. Rev. Lett. 80 4681
[4] Start D.F.H. et al 1999 Nucl. Fusion 39 321
[5] Eriksson L.-G. et al 1999 Nucl. Fusion 39 337
[6] Rimini F.G. et al 1999 Nucl. Fusion 39 1591
[7] Mantsinen M. J. et al 2023, Nucl. Fusion 63 112015