Two-fluid model of rf current condensation in magnetic islands

RF current condensation can stabilize NTMs in tokamaks with less total power and with less localization of the power [1]. The condensation effect relies on positive feedback between the RF deposition and the resulting island temperature perturbation governed by diffusion. The temperature diffusion has previously been modeled with single-fluid approaches [2,3]. However, in regimes where the ion and electron temperatures are not perfectly coupled, qualitatively new physics is introduced. [1] A. H. Reiman and N. J. Fisch, `` Suppression of tearing modes by radio frequency current condensation,'' Phys. Rev. Lett. 121, 225001 (2018) [2] E. Rodr\'{\i}guez, A. H. Reiman, and N. J. Fisch, `` Rf current condensation in magnetic islands and associated hysteresis phenomena,'' Phys. Plasmas 26, 092511 (2019). [3] S. Jin, N. J. Fisch, and A. H. Reiman, `` Pulsed RF schemes for tearing mode stabilization'' Phys. Plasmas 27, 062508 (2020).