The importance of anisotropic interstellar turbulence and molecular-cloud magnetic mirrors for Galactic cosmic-ray propagation

被引:7
作者
Chandran, BDG [1 ]
机构
[1] Univ Iowa, Dept Phys & Astron, Iowa City, IA 52242 USA
关键词
D O I
10.1023/A:1013809502161
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Recent studies suggest that when magnetohydrodynamic (MHD) turbulence is excited by stirring a plasma at large scales, the cascade of energy from large to small scales is anisotropic, in the sense that small-scale fluctuations satisfy the inequality k(parallel to) much less than k(perpendicular to), where k(parallel to) and k(perpendicular to) are, respectively, the components of a fluctuation's wave vector parallel to and perpendicular to to the background magnetic field. Such anisotropic fluctuations are very inefficient at scattering cosmic rays. Results based on the quasilinear approximation for scattering of cosmic rays by anisotropic MHD turbulence are presented and explained. The important role played by molecular-cloud magnetic mirrors in confining and isotropizing cosmic rays when scattering is weak is also discussed.
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页码:271 / 280
页数:10
相关论文
共 15 条
[1]  
Blaauw A., 1952, B ASTRON I NETHERLAN, V11, P405
[2]   COSMIC-RAY CONFINEMENT IN THE GALAXY [J].
CESARSKY, CJ .
ANNUAL REVIEW OF ASTRONOMY AND ASTROPHYSICS, 1980, 18 :289-319
[3]   Scattering of energetic particles by anisotropic magnetohydrodynamic turbulence with a Goldreich-Sridhar power spectrum [J].
Chandran, BDG .
PHYSICAL REVIEW LETTERS, 2000, 85 (22) :4656-4659
[4]   The anisotropy of magnetohydrodynamic Alfvenic turbulence [J].
Cho, JY ;
Vishniac, ET .
ASTROPHYSICAL JOURNAL, 2000, 539 (01) :273-282
[5]   A fractal origin for the mass spectrum of interstellar clouds [J].
Elmegreen, BG ;
Falgarone, E .
ASTROPHYSICAL JOURNAL, 1996, 471 (02) :816-821
[6]   Intercloud structure in a turbulent fractal interstellar medium [J].
Elmegreen, BG .
ASTROPHYSICAL JOURNAL, 1997, 477 (01) :196-203
[7]   TOWARD A THEORY OF INTERSTELLAR TURBULENCE .2. STRONG ALFVENIC TURBULENCE [J].
GOLDREICH, P ;
SRIDHAR, S .
ASTROPHYSICAL JOURNAL, 1995, 438 (02) :763-775
[8]  
HEITHAUSEN A, 1998, A A, V331, P65
[9]   INERTIAL-RANGE SPECTRUM OF HYDROMAGNETIC TURBULENCE [J].
KRAICHNAN, RH .
PHYSICS OF FLUIDS, 1965, 8 (07) :1385-+
[10]   ANISOTROPY IN MHD TURBULENCE DUE TO A MEAN MAGNETIC-FIELD [J].
SHEBALIN, JV ;
MATTHAEUS, WH ;
MONTGOMERY, D .
JOURNAL OF PLASMA PHYSICS, 1983, 29 (JUN) :525-547