Title :
ELM suppression by resonant magnetic perturbations at DIII-D
Author :
Schaffer, M.J. ; Evans, T.E. ; Fenstermacher, M.E. ; Moyer, R.A.
Author_Institution :
Gen. Atomics, San Diego, CA, USA
Abstract :
Edge localized mode (ELM) suppression by resonant magnetic perturbations (RMPs) is being studied at DIII-D with ITER-similar plasma shapes and edge collisionalities. Suppression at low collisionality correlates with overlap of vacuum magnetic field islands in a quantified edge layer at moderate q. Suppression is successful with n = 3 perturbations from one or two rows of internal coils, but it fails for n < 3 and for poloidally-tall and distant coil arrays. These observations are interpreted in terms of differences of spatial helical harmonic spectra the different magnetic perturbations: excessive nonresonant harmonics may brake plasma rotation before the RMP is large enough to suppress ELMs.
Keywords :
Tokamak devices; fusion reactor materials; plasma boundary layers; plasma collision processes; plasma flow; plasma instability; DIII-D; ELM; ITER; distant coil arrays; edge collisionalities; edge localized mode suppression; plasma rotation; plasma shapes; poloidally-tall arrays; resonant magnetic perturbations; spatial helical harmonic spectra; Coils; Magnetic flux; Magnetic resonance; Magnetic separation; Plasma confinement; Plasma density; Plasma displays; Shape; Tokamaks; Toroidal magnetic fields; DIII-D; ELM; RMP; edge localized mode; magnetic perturbations;
Conference_Titel :
Fusion Engineering, 2009. SOFE 2009. 23rd IEEE/NPSS Symposium on
Conference_Location :
San Diego, CA
Print_ISBN :
978-1-4244-2635-5
Electronic_ISBN :
978-1-4244-2636-2
DOI :
10.1109/FUSION.2009.5226535
