Control of the Onset of Magnetic Reconnection in Laser-Plasma Interactions

We conducted an experiment to see the effects of an external perturbation on laser-driven magnetic reconnection (MR). For this experiment, the perturbation was a short pulse laser, impinging on the current sheet between two colliding laser-driven, self-magnetizing plasma plumes. We show that the short pulse can influence the instabilities in the reconnecting current sheet. We conclude that tuning the control of MR depends on the proper (1) SP laser energy, (2) plasma density compared to the SP laser critical density, and (3) density scale length because (i) large SP energy introduces a large plasma-magnetic structure that replaces the current sheet structure between the colliding flows, (ii) the magnetized region may be hidden beneath a critical-density layer and be inaccessible to the laser, and (iii) the density scale length influences both SP laser beam filamentation and the magnetic field generation of each laser filament. Additionally, hot electrons generated by the SP can have magnetic effects that extend beyond the SP focal spot, providing an additional mechanism to influence MR in the laboratory. These results are relevant to understanding the onset and dynamic evolution of reconnecting current sheets under external perturbations, with broader implications for space and astrophysical plasmas.