Magnetic field generation mechanisms of a relativistic laser between colliding magnetized plasma plumes*

Experiments which measure the magnetic fields of laser-driven plasmas give insight into the basic processes of plasmas such as magnetic reconnection. These processes become more difficult to describe when there is a mixture between regimes, such as between relativistic kinetic plasma and MHD-describable plasma, as in this case. In this experiment, a 10-ps, 10^19 W/cm^2 infrared (IR) laser impinged on the interface between two plasma plumes driven by 2.5 ns, 10^14 W/cm^2 ultraviolet (UV) lasers at the OMEGA-EP laser facility. The magnetic fields were measured with proton radiography from a TNSA source. In one regime, the relativistic perturbation inhibited the magnetic reconnection between the two plasma plumes, but with a different timing of the relativistic laser the reconnection may have been enhanced. Probable causes will be discussed. This work is relevant to understanding the physics of reconnection in HED plasmas.