Collisionless reconnection in the large guide field regime: Gyrokinetic versus particle-in-cell simulations

Abstract

Results of the first validation of large guide field, Bg/δB0≫1, gyrokinetic simulations of magnetic reconnection at a fusion and solar corona relevant βi=0.01 and solar wind relevant βi=1 are presented, where δB0 is the reconnecting field. Particle-in-cell (PIC) simulations scan a wide range of guide magnetic field strength to test for convergence to the gyrokinetic limit. The gyrokinetic simulations display a high degree of morphological symmetry, to which the PIC simulations converge when βiBg/δB0 ≫1 and Bg/δB0≫1. In the regime of convergence, the reconnection rate, relative energy conversion, and overall magnitudes are found to match well between the PIC and gyrokinetic simulations, implying that gyrokinetics is capable of making accurate predictions well outside its regime of formal applicability. These results imply that in the large guide field limit many quantities resulting from the nonlinear evolution of reconnection scale linearly with the guide field. © 2014 AIP Publishing LLC.