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Global magnetohydrodynamic simulation of the 15 March 2013 coronal mass ejection event-Interpretation of the 30-80 MeV proton flux

Wu, Chin-Chun and Liou, Kan and Vourlidas, Angelos and Plunkett, Simon and Dryer, Murray and Wu, S. T. and Mewaldt, Richard A. (2016) Global magnetohydrodynamic simulation of the 15 March 2013 coronal mass ejection event-Interpretation of the 30-80 MeV proton flux. Journal of Geophysical Research. Space Physics, 121 (1). pp. 56-76. ISSN 2169-9380. http://resolver.caltech.edu/CaltechAUTHORS:20160317-110712458

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Abstract

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 (r_(cc) ≥ 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)(r_(cc) = 0.87). When scaled by r^(−2.8), the correlation for 10–30 MeV proton flux improves significantly from r_(cc) = 0.12 to r_(cc) = 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.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1002/2015JA021051DOIArticle
http://onlinelibrary.wiley.com/doi/10.1002/2015JA021051/abstractPublisherArticle
Additional Information:© 2015. American Geophysical Union. Received 27 Jan 2015. Accepted 16 Nov 2015. Accepted article online 18 Nov 2015. Published online 23 Jan 2016. The simulation results (~7 GB of data) of this study can be obtained through making a request to the lead author. All data used in this study are obtained from public domain. We thank the Wind and ACE PI teams and National Space Science Data Center at Goddard Space Flight Center, National Aeronautics and Space Administration for their management and providing solar wind plasma and magnetic field data; STEREO and LASCO PI teams for providing coronal images; and Kyoto University for providing geomagnetic activity index (Dst). We thank Olga Malandraki for her constructive suggestions. We also thank Y.M. Wang (NRL) who provided derived solar magnetic fields at 2.5 RSUN. This study is supported partially by Chief Naval Research (CCW, SP), NASA (AV), and NSF base program (KL), AGS1153323 (STW). The Caltech effort was supported by NASA grants NNX13A66G and NNX11A075G. The Hakamada-Akasofu-Fry solar wind model version 2 (HAFv2) was provided to NRL/SSD by a software license from Exploration Physics International, Inc. (EXPI).
Group:Space Radiation Laboratory
Funders:
Funding AgencyGrant Number
Chief Naval ResearchUNSPECIFIED
NSFAGS1153323
NASANNX13A66G
NASANNX11A075G
Subject Keywords:coronal mass ejection; geomagnetic storm; interplanetary shock; MHD simulation; solar energetic particles; magnetic cloud
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory2016-36
Record Number:CaltechAUTHORS:20160317-110712458
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20160317-110712458
Official Citation:Wu, C.-C., K. Liou, A. Vourlidas, S. Plunkett, M. Dryer, S. T. Wu, and R. A. Mewaldt (2016), Global magnetohydrodynamic simulation of the 15 March 2013 coronal mass ejection event—Interpretation of the 30–80 MeV proton flux, J. Geophys. Res. Space Physics, 121, 56–76, doi:10.1002/2015JA021051.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:65432
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:17 Mar 2016 19:26
Last Modified:08 Jul 2016 19:03

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