title: Mechanism of edge localized mode mitigation by resonant magnetic perturbations.
abstract: A possible mechanism of edge localized modes (ELMs) mitigation by resonant magnetic perturbations (RMPs) is proposed based on the results of nonlinear resistive magnetohydrodynamic modeling using the jorek code, realistic JET-like plasma parameters and an RMP spectrum of JET error-field correction coils (EFCC) with a main toroidal number n=2 were used in the simulations. Without RMPs, a large ELM relaxation is obtained mainly due to the most unstable medium-n ballooning mode. The externally imposed RMP drives nonlinearly the modes coupled to n=2 RMP which produce small multimode relaxations, mitigated ELMs. The modes driven by RMPs exhibit a tearinglike structure and produce additional islands. Mitigated ELMs deposit energy into the divertor mainly in the structures ("footprints") created by n=2 RMPs, however, slightly modulated by other nonlinearly driven even harmonics. The divertor power flux during a ELM phase mitigated by RMPs is reduced almost by a factor of 10. The mechanism of ELM mitigation by RMPs proposed here reproduces generic features of high collisionality RMP experiments, where large ELMs are replaced by small, much more frequent ELMs or magnetic turbulence. Total ELM suppression was also demonstrated in modeling at higher RMP amplitude.
authors.affiliation: CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France.
authors.forename: M
authors.initials: M
authors.lastname: Bécoulet
authors.affiliation: CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France.
authors.forename: F
authors.initials: F
authors.lastname: Orain
authors.affiliation: ITER Organization, Route de Vinon-sur-Verdon, 13067 Saint-Paul-Lez-Durance, France.
authors.forename: G T A
authors.initials: GT
authors.lastname: Huijsmans
authors.affiliation: CCFE, Culham Science Centre, Oxon OX14 3DB, United Kingdom.
authors.forename: S
authors.initials: S
authors.lastname: Pamela
authors.affiliation: Institute of Plasma Physics ASCR, 182 00 Prague 8, Czech Republic.
authors.forename: P
authors.initials: P
authors.lastname: Cahyna
authors.affiliation: Max-Planck-Institut, 85748 Garching, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Hoelzl
authors.affiliation: CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France.
authors.forename: X
authors.initials: X
authors.lastname: Garbet
authors.affiliation: Max-Planck-Institut, 85748 Garching, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Franck
authors.affiliation: Max-Planck-Institut, 85748 Garching, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Sonnendrücker
authors.affiliation: CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France.
authors.forename: G
authors.initials: G
authors.lastname: Dif-Pradalier
authors.affiliation: CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France.
authors.forename: C
authors.initials: C
authors.lastname: Passeron
authors.affiliation: CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France.
authors.forename: G
authors.initials: G
authors.lastname: Latu
authors.affiliation: CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France.
authors.forename: J
authors.initials: J
authors.lastname: Morales
authors.affiliation: CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France.
authors.forename: E
authors.initials: E
authors.lastname: Nardon
authors.affiliation: CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France.
authors.forename: A
authors.initials: A
authors.lastname: Fil
authors.affiliation: Laboratoire de Mathématiques J.A. Dieudonné, UMR 7351, CNRS UNS, Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 02, France.
authors.forename: B
authors.initials: B
authors.lastname: Nkonga
authors.affiliation: Laboratoire de Mathématiques J.A. Dieudonné, UMR 7351, CNRS UNS, Université de Nice-Sophia Antipolis, Parc Valrose, 06108 Nice Cedex 02, France.
authors.forename: A
authors.initials: A
authors.lastname: Ratnani
authors.affiliation: CEA, IRFM, 13108 Saint-Paul-Lez-Durance, France.
authors.forename: V
authors.initials: V
authors.lastname: Grandgirard