Numerical Simulation of an Experimental Turbulent Dynamo on the OMEGA-EP Laser

Turbulent dynamos that exponentially amplify initially small, seed magnetic fields are crucial in magnetizing the universe. Until now, the ideal environment for turbulent dynamos to grow has proved difficult to recreate. In a new approach, we leverage the long pulse capability of the OMEGA-EP laser to recreate the highly conductive and inviscid (Re_m ~ 3000, Pr_m ~ 1) growth environment of the turbulent dynamo within the magnetized plasma jet ablated from a simple cone target of CH plastic. In 3-D FLASH simulations of our scheme, we find that the dynamo environment is a typically ~ 0.5 mm³, ~ 1 keV hot spot where the laser beams intersect to produce maximum direct heating of the jet plasma. The dynamo environment is maintained from the onset of steady flows through the ~ 10 ns length of the laser pulse. For a plasma vorticity of 0.3-1.5 ns^-1 and a dynamo active over 2-4 ns, the magnetic energy detectably increases on an exponential trajectory by a factor of a few. By demonstrating the tight dependence of dynamo activity on an easily-controlled variable, i.e. the laser beams, we show that our scheme can readily be extended to study even more complex behaviors.