Abstract: MARFE(Multifaceted asymmetric radiation from the edge), the precursor of  density limit in some observations, has been studied in the 2-D fluid model and observed in multiple tokamak experiments, as well as in the J-TEXT high density discharges with ECRH. To further understand the mechanism of MARFE, some typical density limit shots from J-TEXT are performed with the extended-MHD code called NIMROD (Sovinec et al 2004 J. Comput. Phys. 195 355). First, thermal instability of MARFE is studied. Secondly, through analyzing the time evolution of MARFE, the plasma behaviors and mechanism of density limit disruption are investigated. Finally, the influence of configuration optimization on the density limit in J-TEXT high density discharges is discussed.
 

MARFE;MHD instability;density limit;-1/1 non-Resonant MP