The electron forewake: Shadowing and drift-energization as flowing magnetized plasma encounters an obstacle
Flow of magnetized plasma past an obstacle creates a traditional wake, but also a forewake region arising from shadowing of electrons. The electron forewakes resulting from supersonic flows past insulating and floating-potential obstacles are explored with 2D electrostatic particle-in-cell simula-tions, using a physical ion to electron mass ratio. Drift-energization is discovered to give rise to modifications to the electron velocity-distribution, including a slope-reversal, providing a novel drive of forewake instability. The slope-reversal is present at certain locations in all the simula-tions, and appears to be quite robustly generated. Wings of enhanced electron density are observed in some of the simulations,more »