### Abstract

We present a discussion of the transport of energetic particles in a moving, scattering fluid, which has a large shear in its velocity over a distance small compared with the scattering mean free path. The analysis is complementary to an earlier paper by Earl, Jokipii, and Morfill, which considered effects of more-gradual shear in the diffusion approximation. In the present paper we consider the case in which the scattering fluid undergoes a step function change in velocity, in the direction normal to the flow. We present both an analytical, approximate calculation and a Monte Carlo analysis of particle motion. We find that particles gain energy at a rate proportional to the square of the magnitude of the velocity change. Application to the boundary of a magnetosphere suggests significant acceleration of the particles.

Original language | English (US) |
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Pages (from-to) | 255-258 |

Number of pages | 4 |

Journal | Astrophysical Journal |

Volume | 356 |

Issue number | 1 |

DOIs | |

State | Published - Jun 10 1990 |

### Keywords

- Cosmic rays: general
- Hydrodynamics
- Particle acceleration

### ASJC Scopus subject areas

- Astronomy and Astrophysics
- Space and Planetary Science

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## Cite this

*Astrophysical Journal*,

*356*(1), 255-258. https://doi.org/10.1086/168837