Cyclical generation of reconnected magnetic fields by electron pressure gra-dients

Abstract

The theoretical basis for the cyclical generation of macroscopic reconnected magnetic fields in low collisionality plasma regimes is formulated. The relevant process is sustained by the “thermal” energy of the electron population.In particular, an oscillatory mode propagating along and across a confining magnetic field is identified that involves the magnetic reconnection region where the ratio of the longitudinal to transverse electron thermal conductivity is relatively large. A periodic exchange of reconnected magnetic field conductivity energy with electron thermal energy is sustained within a region that remains significant even when the magnetic field configuration from which the mode can emerge involves large- scale distances. The mode growth rate depends on the particle density gradient (aligned with the electron temperature gradient) and the relevant particle diffusion coefficient. A different magnetic reconnection process driven by the plasma pressure gradient was identified explaining the origin of the observed sawtooth oscillations of magnetically confined plasmas.