Sonic-flow effects on tungsten impurities using the global gyrokinetic PIC code XGC

The usual gyrokinetic ordering [1] orders the E x B drift speed to be small compared to the thermal particle speed. This ordering is not satisfied within many edge, scrape-off-layer, impurity-containing, and strongly-rotating plasmas. However, gyrokinetic equations exist that allow the presence of sonic flows by ordering the vorticity to be small [2]. The equations use the symplectic representation of gyrokinetics, which results in implicit equations. We discuss the implementation of sonic-flow gyrokinetic equations in XGC, based on the existing impurity simulation capability within XGC [3]. We present preliminary results of the effects of sonic flows on tungsten impurities using a model plasma.

[1] Dimits et al., Phys. Fluids B 4, 274 (1992).

[2] Dimits, Phys. Plasmas 17, 055901 (2010).

[3] Dominski et al., J. Plasma Phys. 85, 905850510 (2019).