The dependence of the parallel and perpendicular mean free paths on the rigidity of the solar energetic particles:Theoretical model versus observations
作者单位：Key Laboratory of Ionospheric EnvironmentInstitute of Geology and GeophysicsChinese Academy of Sciences Beijing National Observatory of Space EnvironmentInstitute of Geology and GeophysicsChinese Academy of Sciences Key Laboratory of Solar ActivityNational Astronomical ObservatoriesChinese Academy of Sciences
会议名称：《中国科学院地质与地球物理研究所2013年度（第13届）学术年会》
会议日期：2014年
学科分类：070802[理学-空间物理学] 07[理学] 0708[理学-地球物理学]
基 金：supported in part by the National Natural Science Foundation of China under grants NNSFC 41204130 and NNSFC 41131066 the National Important Basic Research Project under grant 2011CB811405 the Chinese Academy of Sciences under grant KZZD-EW-01- 2 the China Postdoctoral Science Foundation under grants 2011M500381 and 2012T50131 the Open Research Fund of Key Laboratory of Solar Activity, Chinese Academy of Sciences,and the Key Laboratory of Random Complex Structures and Data Science the support of K.C.Wong Education Foundation
关 键 词：interplanetary medium magnetic fields solar terrestrial relations Sun coronal mass ejections flares Sun:particle emission
摘 要：*** dependence of the parallel and perpendicular mean free paths on the particle rigidity is an important topic in the studies of the diffusion and propagation of charged energetic particles in a large-scale turbulent magnetic field. *** this work,we investigate the dependence of the parallel and perpendicular mean free paths on the rigidity of solar energetic particles(SEPs) by means of both the theoretical model and spacecraft observations with regard to several typical SEP events. Methods.A direct method developed by previous studies and derived from the focused transport equation and Taylor-Green-Kubo (TGK) formulation is applied to explicitly determine the parallel and perpendicular mean free paths of SEPs in a turbulent and spatially varying magnetic field. *** find that the parallel and perpendicular mean free paths,λ andλ,of energetic protons monotonically decrease with increasing particle rigidity,and the ratioλ/λmonotonically increases with particle rigidity,when the magnetic turbulence is weak. Taking a series of typical SEP events together,it can also be seen that the ratioλ⊥/λof the perpendicular to the parallel mean free paths remains in the range of 0.001-0.2.