DOI: 10.1002/2015JA021051
论文题名: Global magnetohydrodynamic simulation of the 15 March 2013 coronal mass ejection event - Interpretation of the 30-80 MeV proton flux
作者: Wu C.-C. ; Liou K. ; Vourlidas A. ; Plunkett S. ; Dryer M. ; Wu S.T. ; Mewaldt R.A.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2015
卷: 119, 期: 20 语种: 英语
英文关键词: coronal mass ejection
; geomagnetic storm
; interplanetary shock
; magnetic cloud
; MHD simulation
; solar energetic particles
Scopus关键词: boundary condition
; coronal mass ejection
; extraterrestrial matter
; Gaussian method
; geomagnetic storm
; magnetic field
; magnetohydrodynamics
; simulation
; solar wind
; spacecraft
英文摘要: The coronal mass ejection (CME) event on 15 March 2013 is one of the few solar events in Cycle 24 that produced a large solar energetic particle (SEP) event and severe geomagnetic activity. Observations of SEP from the ACE spacecraft show a complex time-intensity SEP profile that is not easily understood with current empirical SEP models. In this study, we employ a global three-dimensional (3-D) magnetohydrodynamic (MHD) simulation to help interpret the observations. The simulation is based on the H3DMHD code and incorporates extrapolations of photospheric magnetic field as the inner boundary condition at a solar radial distance (r) of 2.5 solar radii. A Gaussian-shaped velocity pulse is imposed at the inner boundary as a proxy for the complex physical conditions that initiated the CME. It is found that the time-intensity profile of the high-energy (>10 MeV) SEPs can be explained by the evolution of the CME-driven shock and its interaction with the heliospheric current sheet and the nonuniform solar wind. We also demonstrate in more detail that the simulated fast-mode shock Mach number at the magnetically connected shock location is well correlated (rcc ≥ 0.7) with the concurrent 30-80 MeV proton flux. A better correlation occurs when the 30-80 MeV proton flux is scaled by r-1.4(rcc = 0.87). When scaled by r-2.8, the correlation for 10-30 MeV proton flux improves significantly from rcc = 0.12 to rcc = 0.73, with 1 h delay. The present study suggests that (1) sector boundary can act as an obstacle to the propagation of SEPs; (2) the background solar wind is an important factor in the variation of IP shock strength and thus plays an important role in manipulation of SEP flux; (3) at least 50% of the variance in SEP flux can be explained by the fast-mode shock Mach number. This study demonstrates that global MHD simulation, despite the limitation implied by its physics-based ideal fluid continuum assumption, can be a viable tool for SEP data analysis. Key Points Sector boundary can act as an obstacle to the propagation of SEPs Background solar wind is an important factor in the variation of shock strength At least 50% of the variance in SEP flux can be explained by the shock Mach number ©2015. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63014
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Naval Research Laboratory, Washington, DC, United States; Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, United States; Space Weather Predictions Center, Emeritus, NOAA, Boulder, CO, United States; CSPAR, University of Alabama, Huntsville, AL, United States; California Institute of Technology, Pasadena, CA, United States
Recommended Citation:
Wu C.-C.,Liou K.,Vourlidas A.,et al. Global magnetohydrodynamic simulation of the 15 March 2013 coronal mass ejection event - Interpretation of the 30-80 MeV proton flux[J]. Journal of Geophysical Research: Atmospheres,2015-01-01,119(20)