# Plasma and Fusion Research

## Volume 6, 2401025 (2011)

# Regular Articles

- Department of Physics, Nagoya University, Nagoya 464-8602, Japan

### Abstract

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 ∼ 10^{4} in a uniform external magnetic field B_{0} is demonstrated with a simulation with the shock speed v_{sh} 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 B_{0} is investigated; comparisons are made of two different cases: 1) the strength of the external magnetic field increases as a shock wave propagates (∇B_{0} is parallel to the wave normal), and 2) it decreases (∇B_{0} is unti-parallel to the wave normal).
It is found that positron acceleration in the latter tends to be stronger than in the former.

### Keywords

ultrarelativistic positron acceleration, electron-positron-ion plasma, magnetosonic shock wave, parallel electric field, particle simulation

### Full Text

### References

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This paper may be cited as follows:

Takashi IWATA, Seiichi TAKAHASHI and Yukiharu OHSAWA, Plasma Fusion Res. 6, 2401025 (2011).