Solar energetic particles intensity variations associated with a tilted-dipole 3D corotating interaction region  

作　　者：YuJi Zhu Fang Shen Xi Luo Yang Wang BoFeng Tang 

机构地区：[1]State Key Laboratory of Space Weather,National Space Science Center,Chinese Academy of Sciences,Beijing 100190,China [2]Shandong Institute of Advanced Technology(SDIAT),Jinan 250100,China [3]College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China [4]School of Science,Harbin Institute of Technology,Shenzhen 518055,China

出　　处：《Earth and Planetary Physics》2024年第5期797-810,共14页地球与行星物理（英文版）

基　　金：jointly supported by the National Natural Science Foundation of China(42330210 and 41974202);the National Key R&D Program of China(grant Nos.2022YFF0503800 and2021YFA0718600);the Strategic Priority Research Program of the Chinese Academy of Sciences(grant No.XDB 41000000);the Specialized Research Fund for State Key Laboratories。

摘　　要：The effect of a tilted-dipole three-dimensional corotating interaction region(CIR)on the transport and acceleration of solar energetic particles(SEPs)is studied.In this work,we discussed how the particle intensity longitudinal and radial dependence might be influenced by the background structures.Moreover,we investigate how the spectral index distribution is modulated by the CIR structure We use the focused transport equation(FTE)to describe the propagation and acceleration of SEPs in a tilt-dipole 3D CIR,generated by the high-resolution 3D magnetohydrodynamic(MHD)model.The forward stochastic differential method is used to solve the FTE.The protons with theE~(-4.4)spectrum from 0.5 to 15 MeV are injected uniformly at the heliographic equator of 0.15 AU.Physical quantities are extracted along each interplanetary magnetic field(IMF)line to show the results.In the tilted-dipole CIR background,if injected from the solar equator at the inner boundary,particles in the slow flow are transported to higher latitudes due to the extension of the IMF lines to higher latitudes.The longitudinal patterns of the particles are dominated by the density of IMF lines.The focusing effect modulates the longitudinal variation of the particle intensity and gives rise to new longitudinal intensity peaks.The adiabatic effect largely increases the intensity fluctuation along the longitude.The structure of the solar wind can also lead to the difference of the indexαin the empirical functionI_(max)=kR~(-α),describing the radial variation of peak intensity according to our simulation.Under the influence of the CIR structure,the indexαvaries from 1.9 to 3.4 at 0.3-1.0 AU.The variation of the solar wind speed should be considered when estimating the radial dependence of the SEP peak intensity.The spectra indices rise near the CIR boundaries and drop near the stream interface(SI).The adiabatic effect makes the spatial variability of the spectral index larger.The spectral index could be similar at different radial distances in the CIR structur

关 键 词：solar energetic particle(SEP) corotating interaction regions(CIR) magnetohydrodynamic(MHD) 

分 类 号：P182[天文地球—天文学] P353