ELM suppression in helium plasmas with 3D magnetic fields

Evans, T. E.; Loarte, A.; Orlov, D. M.; Grierson, B. A.; Knölker, M. M.; Lyons, B. C.; Cui, L.; Gohil, P.; Gröbner, R. J.; Moyer, R. A.; Nazikian, R.; Osborne, T. H. und Unterberg, E. A. (2017): ELM suppression in helium plasmas with 3D magnetic fields. In: Nuclear Fusion, Bd. 57, Nr. 8, 86016

Abstract

Experiments in DIII-D, using non-axisymmetric magnetic perturbation fields in high-purity low toroidal rotation, He-4 plasmas have resulted in Type-I edge localized mode (ELM) suppression and mitigation. Suppression is obtained in plasmas with zero net input torque near the L-H power threshold using either electron cyclotron resonant heating (ECRH) or balanced co- and counter-I-p neutral beam injection (NBI) resulting in conditions equivalent to those expected in ITER's non-active operating phase. In low-power ECRH H-modes, periods with uncontrolled density and impurity radiation excursions are prevented by applying n = 3 non-axisymmetric magnetic perturbation fields. ELM suppression results from a reduction and an outward shift of the electron pressure gradient peak compared to that in the high-power ELMing phase. The change in the electron pressure gradient peak is primarily due to a drop in the pedestal temperature rather than the pedestal density.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Physik
• Themengebiete: 500 Naturwissenschaften und Mathematik > 530 Physik
• ISSN: 0029-5515
• Sprache: Englisch