Abstract Details
Abstracts
Author: Jacobo Varela Rodriguez
Requested Type: Consider for Invited
Submitted: 2024-03-27 15:34:42
Co-authors: J. Garcia, S. Mazzi, Y. Kazakov, Ž. Štancar, M. Baruzzo, J. Ongena, D. Spong, L. Garcia, Y. Ghai, D. Zarzoso, J. Ortiz, M. Poradzinski, JET contributors and EUROfusion Tokamak Exploitation team
Contact Info:
IFS UT-Austin
2515 Speedway
Austin, TX 78712
USA
Abstract Text:
The present study is dedicated to analyze the rich fast ion (FI) induced perturbations in ion cyclotron resonance heating (ICRH) dominated plasmas in JET Deuterium-Tritium (D-T) discharges, the closest experimental campaign to reactor-like operation. A set of nonlinear simulations are performed with the gyro-fluid FAR3d code to reproduce the FI induced activity and energetic particle (EP) transport observed in the discharge #99896 by single EP species as well as multiple EP populations. Well validated simulations with JET diagnostics show that Toroidal Alfvén Eigenmodes (TAEs) and fishbone are destabilized by ICRH accelerated passing D and trapped H ions respectively, leading to negligible EP losses by TAEs although around 5% alpha particle losses by the fish-bones. In addition, the generation of shear flows during the saturation phase of TAEs and fish-bones is observed in the simulations. Shear flows induced by TAEs in the inner-middle plasma region are 4 times larger compared to the shear flows caused by the fish-bone in the inner plasma region. Simulations performed for configuration with a weaker TAE and fish-bone activity show the generation of less intense shear flows, in particular by replacing D-T thermal plasma by a pure D. There is experiment evidence of an improved thermal plasma confinement in D-T discharges compared to pure D discharges linked to stronger AE / fish-bone activity, thus shear flows may reduce the plasma turbulence and enhance the thermal plasma confinement. Consequently, shear flow generation by AE / fish-bones may have an important impact in the thermal plasma confinement of devices as ITER and JT60SA where they are expected to be destabilized by the large FI population. It is shown that this is a fundamental result that has to be considered to properly evaluate fusion power in reactor relevant plasmas.
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