title: Observation of a multimode plasma response and its relationship to density pumpout and edge-localized mode suppression.
abstract: Density pumpout and edge-localized mode (ELM) suppression by applied n=2 magnetic fields in low-collisionality DIII-D plasmas are shown to be correlated with the magnitude of the plasma response driven on the high-field side (HFS) of the magnetic axis but not the low-field side (LFS) midplane. These distinct responses are a direct measurement of a multimodal magnetic plasma response, with each structure preferentially excited by a different n=2 applied spectrum and preferentially detected on the LFS or HFS. Ideal and resistive magneto-hydrodynamic (MHD) calculations find that the LFS measurement is primarily sensitive to the excitation of stable kink modes, while the HFS measurement is primarily sensitive to resonant currents (whether fully shielding or partially penetrated). The resonant currents are themselves strongly modified by kink excitation, with the optimal applied field pitch for pumpout and ELM suppression significantly differing from equilibrium field alignment.
authors: General Atomics, San Diego, California 92121, USA.
authors: C
authors: C
authors: Paz-Soldan
authors: Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
authors: R
authors: R
authors: Nazikian
authors: Plasma Research Laboratory, Australian National University, Canberra, Australian Capital Territory 0200, Australia.
authors: S R
authors: SR
authors: Haskey
authors: Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
authors: N C
authors: NC
authors: Logan
authors: General Atomics, San Diego, California 92121, USA.
authors: E J
authors: EJ
authors: Strait
authors: General Atomics, San Diego, California 92121, USA.
authors: N M
authors: NM
authors: Ferraro
authors: Columbia University, New York, New York 10027, USA.
authors: J M
authors: JM
authors: Hanson
authors: General Atomics, San Diego, California 92121, USA.
authors: J D
authors: JD
authors: King
authors: General Atomics, San Diego, California 92121, USA.
authors: M J
authors: MJ
authors: Lanctot
authors: University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0417, USA.
authors: R A
authors: RA
authors: Moyer
authors: Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
authors: M
authors: M
authors: Okabayashi
authors: Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
authors: J-K
authors: JK
authors: Park
authors: Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, Tennessee 37831-6169, USA.
authors: M W
authors: MW
authors: Shafer
authors: Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
authors: B J
authors: BJ
authors: Tobias