Speaker
Description
This talk introduces the application of a Hamiltonian gyrofluid approach to investigate magnetic reconnection and associated secondary instabilities, while considering finite Larmor radius corrections, parallel magnetic field fluctuations, and electron inertia. During the nonlinear development of spontaneous magnetic reconnection, non-collisional current sheets form, characterized by their small thickness similar to the electron skin depth. These sheets can become unstable, leading to the formation of plasmoids and facilitating high reconnection rates. We examine the marginal stability conditions for plasmoid formation in collisionless plasma, specifically focusing on the impact of finite but moderate βe, which has received limited attention previously. Our study shows that plasmoids can be obtained, in this context, from current sheets with an aspect ratio much smaller than in the collisional regime, and that the plasma flow channel of the marginally stable current layers maintains an inverse aspect ratio of 0.1. Our findings are validated through gyrokinetic simulations, demonstrating excellent agreement.
Moreover, we shall present preliminary results obtained in the regime of small βe and hot ions. we investigate the turbulent regime that arises from Kelvin-Helmholtz-like secondary instabilities outside magnetic islands, resulting in the creation of magnetic vortices.
