COSMIC-RAY PERPENDICULAR DIFFUSION-COEFFICIENT COMPUTED USING VOYAGER DATA AT 15-AU

被引:11
作者
VALDESGALACIA, JF
QUENBY, JJ
MOUSSAS, X
机构
[1] UNIV LONDON IMPERIAL COLL SCI TECHNOL & MED,LONDON SW7 2BZ,ENGLAND
[2] UNIV ATHENS,ASTROPHYS LAB,GR-15783 ATHENS,GREECE
关键词
D O I
10.1007/BF00147889
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Perpendicular diffusion due to either field line wandering or random gradient and curvature effects makes a substantial contribution to the radial transport of particles at distances of about 5 AU and beyond when lines of the interplanetary magnetic field (IMF) become almost azimuthal. Here test particle trajectories are followed in a field model which uses a magnetic field sample taken by Voyager 2 at 14.8 AU. Techniques previously developed (Moussas et al., 1982a) are employed to calculate the perpendicular diffusion coefficient for 100 MeV protons and arising from random gradient and curvature effects. The result K(perpendicular-to) = (2.8 +/- 0.9) x 10(21) cm2 s-1 shows a substantial increase above the value determined previously at 5 AU and, assuming a power law radial dependence K approximately r(beta) implies beta congruent-to 0.8-1.1. This result is consistent with observations of the cosmic-ray radial gradient.
引用
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页码:189 / 199
页数:11
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