### 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) |
---|---|

Pages (from-to) | 255-258 |

Number of pages | 4 |

Journal | Astrophysical Journal |

Volume | 356 |

Issue number | 1 |

State | Published - Jun 10 1990 |

### Fingerprint

### Keywords

- Cosmic rays: general
- Hydrodynamics
- Particle acceleration

### ASJC Scopus subject areas

- Space and Planetary Science

### Cite this

*Astrophysical Journal*,

*356*(1), 255-258.

**Particle acceleration in step function shear flows : A microscopic analysis.** / Jokipii, J. Randy; Morfill, G. E.

Research output: Contribution to journal › Article

*Astrophysical Journal*, vol. 356, no. 1, pp. 255-258.

}

TY - JOUR

T1 - Particle acceleration in step function shear flows

T2 - A microscopic analysis

AU - Jokipii, J. Randy

AU - Morfill, G. E.

PY - 1990/6/10

Y1 - 1990/6/10

N2 - 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.

AB - 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.

KW - Cosmic rays: general

KW - Hydrodynamics

KW - Particle acceleration

UR - http://www.scopus.com/inward/record.url?scp=0012156725&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0012156725&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:0012156725

VL - 356

SP - 255

EP - 258

JO - Astrophysical Journal

JF - Astrophysical Journal

SN - 0004-637X

IS - 1

ER -