Turbulent reconnection driven by kinetic instabilities in colliding laser-produced plasmas*

Magnetic reconnection experiments are conducted in a low-collisionality regime at the OMEGA EP facility. Magnetic fields are generated in expanding plasmas by the Biermann battery effect. Collision of multiple plasma bubbles produces a magnetic reconnection current sheet and drives magnetic reconnection. A novel aspect of these experiments is that a gap is introduced between the targets lowering the plasma density at the reconnection layer, and allowing high resolution proton radiography. Proton radiography reveals, for the first time, a cascade of plasmoid instabilities from short wavelength to long wavelength. The initial short-wavelength tearing is strongly modified by plasma anisotropy driven by the counter-streaming flows forming the current sheet, and is a hybrid of Weibel and tearing instability. The results have implications for magnetic reconnection driven in low-collisionality, compressive systems such as planetary magnetospheres and the heliosheath. Results on particle energization during reconnection will be reported.