Studying astrophysical particle acceleration mechanisms with colliding magnetized laser-produced plasmas

Significant particle energization is observed to occur in many astrophysical environments, and in the standard models this acceleration occurs as a part of the energy conversion processes associated with collisionless shocks or magnetic reconnection. A recent generation of laboratory experiments conducted using magnetized laser-produced plasmas has opened opportunities to study these particle acceleration processes in the laboratory. Ablated plasma plumes are externally magnetized using an externally-applied magnetic field in combination with a low-density background plasma. Colliding unmagnetized plasmas demonstrated ion-driven Weibel instability [1] while colliding magnetized plasmas drive magnetic reconnection [2]. Both magnetized and unmagnetized colliding plasma are modeled with electromagnetic particle-in-cell simulations which provide an end-to-end model of the experiments. Using particle-in-cell simulations, we provide predictions of particle acceleration driven by reconnection, resulting from both direct x-line acceleration and Fermi-like acceleration at contracting magnetic fields lines near magnetic islands.\\[4pt] [1] W. Fox, G. Fiksel, A. Bhattacharjee, et al, PRL 111, 225002 (2013).\\[0pt] [2] G. Fiksel, W. Fox, A. Bhattacharjee, et al, PRL 113, 105003 (2014).