Laser-driven magnetic reconnection and particle acceleration by snail-shaped target irradiation*

Magnetic reconnection is a process of magnetic field topology rearrangement which converts magnetic field energy into energy of charged particles through the magnetic reconnection outflow.

In this work, we report a laboratory experiment scheme of magnetic reconnection study by using high intensity laser irradiation of a snail-shaped target. In our experiment, a magnetized plasmoid with magnetic field magnitude of about several kilo-teslas and with anti-parallel geometry was produced inside the target volume. The magnetic field magnitude and structure was characterized by proton radiography measurements. As the consequence of magnetic reconnection, ions are accelerated along the outflow direction and current sheet direction were separately observed in the experiment. In both directions, we observed proton beams with conversion efficiency comparable to the Target Normal Sheath Acceleration(TNSA) scheme. This also showed the potential of the presented setup as an alternative laser-driven ion acceleration scheme.

3-D PIC simulations are performed for further understanding of above phenomenon. Simulation results would be discussed in detail, especially about the details of particle acceleration mechanism.