Kinetic Theory of Driven Magnetic Reconnection

Particle-in-cell (PIC) simulations of driven magnetic reconnection have revealed important physical processes such as the penetration of the driving electric field into the reconnection region, the creation of charge separation and electrostatic potential, and the generation of the parallel electric field.1-3 The driving electric field, the electrostatic electric field and the parallel electric field strongly control the plasma heating/acceleration processes during the driven magnetic reconnection. The PIC simulations have also shown how and where electrons and ions are accelerated/heated, which are consistent with the electron and ion heating results obtained in the laboratory magnetic reconnection experiments.4-7 We have developed analytical theory in the zero guide field case to understand how the electron and ion dynamics decouple in the reconnection layer and the separatrix regions and how the parallel electric field and electrostatic electric field are produced. The analytical theory provides understanding of the particle dynamics and heating/acceleration processes in these critical reconnection regions as observed in the PIC simulations. The analytical theory also allows to scale the PIC simulation results to plasma conditions in laboratory experiments and space plasmas. In particular, we provide an analytical scaling to understand that the increase of ion temperature is proportional to the square of the upstream Alfven velocity.

References:

1. C. Z. Cheng et al., Phys. Plasmas 22, 101205 (2015). 2. C. Z. Cheng et al., Plasma Fusion Res. 11, 1401081 (2016). 3. S. Inoue, et al., Nucl. Fusion 55, 083014 (2015). 4. Y. Ono, et al., Phys. Rev. Lett. 107, 185001 (2011). 5. Y. Ono, et al., Plasma Phys. Contr. Fusion 54, 124039 (2012). 6. H. Tanabe, et al., Phys. Rev. Lett. 115, 215004 (2015). 7. H. Tanabe, et al., Nucl. Fusion 57, 05603 (2017)