Studies of Biermann-battery driven magnetized collisionless shock precursors at OMEGA

Collisionless shocks are common in the universe. Different types of collisionless shocks can be formed under different circumstances. In this presentation, we report on the first observation of magnetized collisionless shock precursors formed by the compression of Biermann-battery magnetic fields in laser produced plasmas. At OMEGA, a CH plasma flow with frozen-in Biermann fields collides with a hydrogen gas jet to produce a shock precursor. Imaging 2ω Thomson scattering shows that the interaction is collisionless and shows density and temperature jumps. Proton radiography data show strong deflections and FLASH MHD simulations estimate a lower bound on the enhanced magnetic field. This indicates that the precursor is supercritical with M_A ∼ 11. Electrons are also accelerated into a power-law spectrum likely by the shock drift acceleration mechanism.