Visualizing electromagnetic fields in laser-produced counterstreaming plasma experiments for collisionless shock laboratory astrophysics

In astrophysical settings, large and stable structures often emerge from turbulent supersonic plasma flows. Examples include the cosmic magnetic field and the collisionless shocks [1] in supernova remnants. In a scaled environment created with the high power lasers at OMEGA EP, proton imaging shows that large, stable electromagnetic field structures arise within counterstreaming supersonic plasmas [2]. These field structures are large compared to the fundamental turbulence scale lengths of the plasma (e.g. the Debye length and the ion skin-depth), indicating a high degree of self-organization. These features remain in place from 4 to 7 ns, indicating a high degree of stability. At early times out to at least 8 ns, \textit{intra}-jet ion collisions are strong (due to relatively low thermal velocities) but \textit{inter}-jet ion collisions are rare (due to relatively high flow velocities), permitting the evolution of both hydrodynamic and collisionless plasma instabilities [3, 4]. This paper will present detailed results from our laboratory astrophysics experiments. Prepared by LLNL for US DOE under Contract DE-AC52-07NA27344.\\[4pt] [1] H. S. Park et al, HEDP, 8, 38 (2011).\\[0pt] [2] N.L. Kugland et al, submitted to Nature Physics (2012).\\[0pt] [3] J.S. Ross et al, Phys. Plas., 19, 056501 (2012).\\[0pt] [3] D.D. Ryutov et al, Phys. Plas., 19, 076532 (2012).