Impact of rotating resonant magnetic perturbation fields on plasma edge electron density and temperature

作者：Stoschus H^*; Schmitz O; Frerichs H; Reiser D; Jakubowski M W; Unterberg B; Lehnen M; Reiter D; Samm U

来源：Nuclear Fusion, 2012, 52(8): 083002.

DOI：10.1088/0029-5515/52/8/083002

Rotating resonant magnetic perturbation (RMP) fields impose a characteristic modulation to the edge electron density n(e)(r, t) and temperature T-e(r, t) fields, which depends on the relative rotation f(rel) between external RMP field and plasma fluid. The n(e)(r, t) and T-e(r, t) fields measured in the edge (r/a = 0.9-1.05) of TEXTOR L-mode plasmas are in close correlation with the local magnetic vacuum topology for low relative rotation f(rel) = -0.2 kHz. In comparison with the 3D neutral and plasma transport code EMC3-Eirene, this provides substantial experimental evidence that for low relative rotation level and high resonant field amplitudes (normalized radial field strength B-r(4/1)/B-t = 2 x 10(-3)), a stochastic edge with a remnant island chain dominated by diffusive transport exists. Radially outside a helical scrape-off layer, the so-called laminar zone embedded into a stochastic domain is found to exist. In contrast for high relative rotation of f(rel) = 1.8 kHz, the measured modulation of n(e) is shifted by pi/2 toroidally with respect to the modelled vacuum topology. A pronounced flattening in T-e(r) and a reduction in n(e)(r) is measured at the resonant flux surface and represents a clear signature for a magnetic island, which is phase shifted with respect to the vacuum island position. A correlated shift of the laminar zone radially outwards at the very plasma edge is observed suggesting that the actual near-field structure at the perturbation source is determined by the plasma response as well.

• 出版日期2012-8