Dreval, M.

Duval, B.

Garcia-Munoz, M.

Karpushov, A.

Lauber, P.

Poley-Sanjuan, J.

Sharapov, S.

Vallar, M.

English

MPG.PuRe

Energetic particle modes in TCV with two neutral beam injectorsM. Vallar1, M. Dreval2, B. Duval1, M. Garcia-Munoz3,4, S. Sharapov5, J. Poley-Sanjuan1, A.Karpushov1,P. Lauber6, the TCV team*1 École Polytech. Féd. de Lausanne (EPFL), Swiss Plasma Center (SPC), Lausanne, Switzerland2 National Science Centre, Kharkiv, Ukraine3 Centro Nacional de Aceleradores (University of Seville, CSIC, J. de Andalucia), Seville, Spain4 Department of Atomic, Molecular and Nuclear Physics, University of Seville, Seville, Spain5 CCFE, Culham Science Centre, Abingdon, United Kingdom of Great Britain and Northern Ireland6 Max-Planck Institute for Plasma Physics, Garching, GermanyTCV is equipped with two Neutral Beam Injectors (NBI), injecting particles tangentially and inopposite toroidal direction at the energies of 25 keV and 50 keV. The additional power coupledto the plasma allows to enter easily H-mode and perform power exhaust studies. In addition,Alfvènic modes have been observed in the presence of both beams, with different combinationsof injection energy, power and geometry. Energetic particle modes are critical for ITER andtheir control is critical for the safety of the device. Understanding the presence of such modesin TCV will improve our capability to control Alfvènic modes thanks to the shaping capabili-ties and electron cyclotron heating in TCV. In TCV, modes with co-current beam feature strongchirping behavior (i.e. quick change in frequency), while modes with counter-injected beamhave a steadier frequency. The reason behind this observation could be given by the amount offast particles confined in TCV plasma: the fast ion pressure is so high that the drive/dampingbalance is modified. In the counter-current case, a reduction of ∼ 10/15% in the neutron ratesis observed when the modes are present. In this work, the modelling of the MHD stability usingTRANSP [1] and LIGKA [2] codes is performed, comparing the separate scenarios where suchmodes have been observed. This allows to quantify the fast particle content and estimate the ad-ditional transport induced by such MHD activity, comparing (when possible) the experimentallymeasured neutron rates and the simulated ones.References[1] RJ Hawryluk. In: Physics of plasmas close to thermonuclear conditions. Elsevier, 1981,pp. 19–46.[2] Ph Lauber et al. In: Journal of Computational Physics 226.1 (2007), pp. 447–465.*See author list of S. Coda et al 2019 Nucl. Fusion 59 112023 (https://doi.org/10.1088/1741-4326/ab25cb) forthe TCV team.48th EPS Conference on Plasma Physics O4.110

Energetic particle modes in TCV with two neutral beam injectors

http://hdl.handle.net/21.11116/0000-000C-1786-3

Energetic particle modes in TCV with two neutral beam injectors

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MPG.PuRe