Title | Power balance analysis at the L-H transition in JET-ILW NBI-heated deuterium plasmas |
Publication Type | Journal Article |
Year of Publication | 2022 |
Authors | P. Vincenzi, E.R. Solano, E. Delabie, C. Bourdelle, G. Snoep, A. Baciero, G. Birkenmeier, P. Carvalho, M. Cavedon, J. Citrin, M. Chernyshova, J. Fontdecaba, J.C. Hillesheim, A. Huber, C. Maggi, S. Menmuir, F.I. Parra, JET Contributors |
Journal | Plasma Physics and Controlled Fusion |
Volume | 64 |
Issue | 12 |
Pagination | 124004 |
Abstract | The understanding of the physics underlying the L-H transition has strong implications for ITER experimental reactor and demonstration power plant (DEMO). In many tokamaks, including JET, it has been observed that, at a particular plasma density, n e,min , the power necessary to access H-mode P L-H is minimum. In the present work, L-H transitions of JET deuterium plasmas heated by neutral beam injection (NBI) are studied for the first time by means of a power balance analysis to characterize the main contributions in the transition, through integrated transport modelling. In the pulses analysed, we do observe a minimum of the L-H power threshold in density, indicating the presence of density branches and of n e,min . Electron and ion heat fluxes at the transition are estimated separately. The electron/ion equipartition power results in favour of the ions, as shown by QuaLiKiz quasilinear gyrokinetic simulations, which predict a larger ion transport that causes T e > T i. The resulting edge ion heat flux also shows a clear change of slope below n e,min , similarly to ASDEX-Upgrade (AUG) NBI pulses (Ryter et al 2014 Nucl. Fusion 54 083003). JET NBI data are compared to radio-frequency heated AUG and Alcator C-mod pulses (Schmidtmayr et al 2018 Nucl. Fusion 58 056003), showing a different trend of the power, coupled to ions at the L-H transition with respect to the linearity observed in the radio-frequency heated plasmas. The presence of n e,min and the role of the ion heat flux is discussed in the paper, although it seems it is not possible to explain the presence of a P L-H minimum in density by a critical ion heat flux and by the equipartition power for the JET NBI-heated plasmas analysed. |
DOI | 10.1088/1361-6587/ac97c0 |
Division | FP |
Department | IMT |
PID | a31a978dcb13ad329cbe018a160bf95f |
Alternate Title | Plasma Phys. Control. Fusion |
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