Digitale Medien
New York, NY
:
American Institute of Physics (AIP)
Physics of Fluids
3 (1991), S. 2124-2132
ISSN:
1089-7666
Quelle:
AIP Digital Archive
Thema:
Physik
Notizen:
The freshly created ions in the upstream region of the cometary bow shock usually form a ring-beam velocity distribution in the solar wind frame of reference. These newborn ions subsequently excite a variety of instabilities which in turn cause the ions to diffuse in pitch angle space to form a quasispherical shell velocity distribution. Such a process can be described by quasilinear kinetic theory. In the present paper, the detailed properties of the initial diffusion rates associated with the cometary newborn ions are studied for various physical parameters including the so-called injection angle α (that is, the average initial pitch angle associated with the ions) ranging from 0° (pure beam distribution) to 90° (pure ring distribution). It is shown that initial diffusion rates are strongly dependent upon the angle α, such that for 0°≤α≤60° (quasiparallel regime) the pitch angle diffusion rate remains relatively small, while for 60°≤α≤90° (quasiperpendicular regime) the diffusion rate increases substantially.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1063/1.859625
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