Magnetic Reconnection Driven by Thermal and Non-thermal Particle Energy Densities

Magnetic reconnection is usually associated with conversion of magnetic energy into particle acceleration or thermal energy. However, a specific reconnection process driven by plasma pressure gradients was identified in Ref. [1] with a consistent theory of (non-ideal) MHD m⁰=1 modes in well confined plasmas. This process, based on an Ohm's law contribution to the electron balance equations, remains the basis for the explanation of the observed sawtooth oscillations of the central plasma pressure and for the inferred magnetic field structures due to fishbone oscillations [2] associated with injected high energy particle populations. A novel process [3] expected to have a wide range of applications concerns magnetic reconnection sustained by a significant gradient of the longitudinal electron temperature and based on the electron thermal energy balance equation rather than on an Ohm's law. A comparison is made with the Biermann Battery concept considering that the growth of reconnection depends on the particle density gradient in addition to that (aligned with it) of the electron temperature.

[1] B. Coppi et al. Fizika Plasmi 6, 961 (1976).

[2] B. Coppi and F. Porcelli, Phys. Rev. Lett. 57, 2272 (1986).

[3] B. Coppi and B. Basu, Phys. Lett. A, 397, 127265 (2021).