Analysis of Alfven eigenmode destabilization by energetic particles in Large Helical Device using a Landau-closure model

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Show simple item record Varela, Jacobo Spong, Donald García Gonzalo, Luis 2021-05-07T08:43:36Z 2021-05-07T08:43:36Z 2017-04
dc.identifier.bibliographicCitation Varela, J., Spong, D. & Garcia, L. (2017). Analysis of Alfvén eigenmode destabilization by energetic particles in Large Helical Device using a Landau-closure model. Nuclear Fusion, 57(4), 046018.
dc.identifier.issn 0029-5515
dc.description.abstract Energetic particle populations in nuclear fusion experiments can destabilize the Alfven Eigenmodes through inverse Landau damping and couplings with gap modes in the shear Alfven continua. We use the reduced MHD equations to describe the linear evolution of the poloidal flux and the toroidal component of the vorticity in a full 3D system, coupled with equations of density and parallel velocity moments for the energetic particles. We add the Landau damping and resonant destabilization effects using a closure relation. We apply the model to study the Alfven mode stability in the inward-shifted configurations of the Large Helical Device (LHD), performing a parametric analysis of the energetic particle beta(beta(f)) in a range of realistic values, the ratios of the energetic particle thermal/Alfven velocities (V-th/V-A0), the magnetic Lundquist numbers (S) and the toroidal modes (n). The n = 1 and n = 2 TAEs are destabilized, although the n = 3 and n = 4 TAEs are weakly perturbed. The most unstable configurations are associated with the density gradients of energetic particles in the plasma core: the TAEs are destabilized, even for small energetic particle populations, if their thermal velocity is lower than 0.4 times the Alfven velocity. The frequency range of MHD bursts measured in the LHD are 50-70 kHz for the n = 1 and 60-80 kHz for the n = 2 TAE, which is consistent with the model predictions.
dc.description.sponsorship This material is based on work supported both by the U.S. Department of Energy and the Office of Science, under contract DE-AC05-00OR22725 with UT-Battelle, LLC. The research was sponsored in part by the Ministerio de Economia y Competitividad of Spain under project no. ENE2015-68265-P. We also want to acknowledge the LHD group at NIFS for providing us with the VMEC equilibria, and useful interactions with Y. Todo and M. Osakabe.
dc.format.extent 13
dc.language.iso eng
dc.publisher IOP Publishing
dc.rights © 2017 IAEA, Vienna
dc.subject.other Stellarator
dc.subject.other LHD
dc.subject.other MHD
dc.subject.other Alfven eigenmodes
dc.subject.other Energetic particles
dc.title Analysis of Alfven eigenmode destabilization by energetic particles in Large Helical Device using a Landau-closure model
dc.type article
dc.subject.eciencia Física
dc.rights.accessRights openAccess
dc.relation.projectID Gobierno de España. ENE2015-68265-P
dc.type.version acceptedVersion
dc.identifier.publicationfirstpage 046018
dc.identifier.publicationissue 4
dc.identifier.publicationtitle Nuclear Fusion
dc.identifier.publicationvolume 57
dc.identifier.uxxi AR/0000020346
dc.contributor.funder Ministerio de Economía y Competitividad (España)
dc.affiliation.dpto UC3M. Departamento de Física
dc.affiliation.grupoinv UC3M. Grupo de Investigación: Física de Plasmas
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