Characterization of asymmetric counter-streaming plasma flows to study quasi-parallel magnetized collisionless shock formation

Collisionless shocks that form in the presence of an ambient magnetic field are the likely source of the highest energy cosmic rays in our universe. Both the magnetic field amplitude, through the Alfvénic Mach number (M_A), and the field orientation relative to the plasma flow will dictate the formation mechanism of the collisionless shocks. The quasi-parallel configuration has shown to produce efficient particle acceleration in satellite measurements [Johlander ApJ 914 (2021)] and in numerical studies [Caprioli ApJ 783 (2014)]. Laser-based experiments provide a unique means to create relevant plasma conditions to study the microphysics associated with electromagnetic field generation relevant to quasi-parallel collisonless-shock formation. To this end, we have developed a new experimental platform at the Omega Laser Facility to study the early stages of quasi-parallel collisionless shock formation by characterizing the conditions of interpenetrating magnetized, asymmetric plasma flows at high M_A (>100) to identify the streaming instabilities generated therein. Plasma parameters in the interaction region are characterized using time-resolved and spatially resolved Thomson scattering. Experimental determination of these conditions helps to identify streaming instabilities that mediate quasi-parallel collisionless shock formation. Recent experimental results will be shown and discussed.