Current Research:
Magnetic Reconnection and Thin Current Sheets
Magnetic reconnection is ubiquitous in nature and the understanding of its onset in collisionless plasmas has been one of the key problems of space plasma physics. The reconnection process takes place in thin current sheets and the understanding of the inter relationship of these processes is crucial to reconnection studies. The tearing instability has been considered the key instability that initiates reconnection and its theory is complicated due the complex magnetic geometry of the thin current sheets and the kinetic nature of the processes. Using a novel approach that takes into account these complicated but essential issues the tearing mode eigenmode has been analyzed and the conditions for the instability elucidated. The key role is played by a population of electrons that is not trapped in the current sheet, thus enabling it to short the electric field that stabilizes the mode. This explains in particular the spontaneous reconnection in the tail of Earth's magnetosphere during substorms and is important in understanding reconnection in other settings.