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 |
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Keywords
- Cosmic rays: general
- Hydrodynamics
- Particle acceleration
ASJC Scopus subject areas
- Space and Planetary Science
Cite this
Particle acceleration in step function shear flows : A microscopic analysis. / Jokipii, J. Randy; Morfill, G. E.
In: Astrophysical Journal, Vol. 356, No. 1, 10.06.1990, p. 255-258.Research output: Contribution to journal › Article
}
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 -