Influence of magnetic island on edge plasma flows and turbulence properties in J-TEXT

Magnetic islands in magnetically confined plasmas are found to have significant effects on the profiles and cross-field transport [1]. And the multi-scale physics such as the interaction between large-scale MHD modes and turbulence are reported to play a crucial role in the transport regulation [2].

In the recent campaign on J-TEXT tokamak, a new experiment has been carried out which aimed to study the plasma flows and turbulences nearby static magnetic islands, using the Langmuir probe and laser collective scattering system. The edge 3/1 island has been excited by applying the resonant magnetic perturbation (RMP) with dominate m/n=3/1 component to a plasma with edge safety factor q_a>~3. This research mainly focuses on three aspects: the effects of variant island size, island location and island phase. Once the condition of 3/1 island has been changed, the radial profiles of plasma density (n_e), temperature (T_e), floating potential (V_f) etc measured by Langmuir probe varied significantly, and the plasma flow and turbulence are also modulated obviously.

[1] Inagaki S. et al 2004 Phys. Rev. Lett. 92 055002

[2] Choi M.J. et al 2017 Nucl. Fusion 57 126058