Co-current toroidal rotation-driven and turbulent stresses with resonant magnetic perturbations in the edge plasmas of the J-TEXT tokamak

Abstract

The acceleration of the co-current toroidal rotations around resonant surfaces by resonant magnetic perturbations (RMPs) through turbulence is presented. These experiments were performed using a Langmuir probe array in the edge plasmas of the J-TEXT tokamak. This study aims at understanding the RMP effects on edge toroidal rotations and exploring its control method. With RMPs, the flat electron temperature Te profile due to magnetic islands appears around resonant surfaces [K. J. Zhao et al., Nucl Fusion, 55, 073022 (2015)]. When the resonant surface is closer to the last closed flux surface, the flat Te profile vanishes with RMPs. In both cases, the toroidal rotations significantly increase in the direction of the plasma current around resonant surfaces with RMPs. The characteristics of turbulence are significantly affected by RMPs around resonant surfaces. Turbulence intensity profile changes and the poloidal wave vector kθ increases with RMPs. The power fraction of the turbulence components in the ion diamagnetic drift direction increases with RMPs. 2The measurements of turbulent Reynolds stresses are consistent with that the toroidal flows can be driven by turbulence. The estimations of the energy transfer between turbulence and toroidal flows suggest that turbulence energy transfers into toroidal flows. The result has the implication of the intrinsic rotation being driven by RMPs via turbulence.

Temporal-spatial structures of plasmas flows and turbulence around tearing mode islands in the edge tokamak plasmas

“…The poloidal flows are reversed when the RMP induced island width is large enough [17]. The static island can enhance the low frequency flows and turbulence at their boundaries [18,19]. The turbulence is weak inside magnetic islands that is consistent with the observations of low gradient of electron temperature [20], and reduced electron thermal conductivity [21].…”

“…The poloidal flows are reversed when the RMP-induced island width is large enough [17]. The static island can enhance the low frequency flows and turbulence at their boundaries [18][19].…”

Mesoscale electric fluctuations interacting with zonal flows, magnetic fluctuations and turbulence

“…The effects of magnetic perturbation on zonal flows were reported. For instance, the GAM is damped in the presence of RMPs [15]; the RMPinduced magnetic islands can enhance the LFZFs and turbulence, and accelerate the edge toroidal rotation [16,17]; the poloidal flows are reversed when the RMPinduced island width is large enough [18]; a quasi coherent mode is detected near the low safety factor rational surface [19,20]. However, the dynamical and mutual interaction between flows and magnetic perturbations has not been deeply studied experimentally.…”

Enhancements of residual Reynolds stresses by magnetic perturbations in the edge plasmas of the J-TEXT tokamak

“…The co-and countercurrent toroidal rotations are accelerated by deeply penetrating RMPs of m/n = 3/1 mode configuration [36] and by RMPs with small injected neutral beam momentum [37], respectively. The acceleration of the toroidal rotation due to RMPs was also observed in tokamak edge plasmas [19,[32][33][34]. The correlation between the acceleration of toroidal rotations and turbulence with RMPs has been examined [19].…”

“…The acceleration of the toroidal rotation due to RMPs was also observed in tokamak edge plasmas [19,[32][33][34]. The correlation between the acceleration of toroidal rotations and turbulence with RMPs has been examined [19].…”