The electron foreshock at high-Mach-number non-relativistic oblique shocks

In the Universe, matter outside of stars and compact objects is mostly composed collisionless plasma. The interaction a supersonic plasma flow with an obstacle results in shocks that are often associated intense nonthermal radiation production cosmic ray particles. Motivated by simulations non-relativistic high-Mach-number supernova remnants, we investigate instabilities excited relativistic electron beams extended foreshock oblique shocks. phase-space distributions inner outer regions derived particle-in-cell simulation shock used as initial conditions for periodic boundary to study their relaxation toward equilibrium. We find observed electron-beam agree very well predictions linear dispersion analysis: electrostatic electron-acoustic instability dominates region foreshock, while denser drive gyroresonant oblique-whistler instability.