2011 Volume 6 Pages 2401025
Ultrarelativistic positron acceleration along the magnetic field due to shock waves in an electron-positron-ion plasma is studied with use of one-dimension (one space coordinate and three velocities), fully kinetic, fully electromagnetic, particle simulations. First, ultrarelativistic acceleration to γ ∼ 104 in a uniform external magnetic field B0 is demonstrated with a simulation with the shock speed vsh close to c cos θ, where c is the speed of light and θ is the angle between the external magnetic field and the wave normal. Then, the effect of non-uniformity of B0 is investigated; comparisons are made of two different cases: 1) the strength of the external magnetic field increases as a shock wave propagates (∇B0 is parallel to the wave normal), and 2) it decreases (∇B0 is unti-parallel to the wave normal). It is found that positron acceleration in the latter tends to be stronger than in the former.
