University of Oulu

Kocharov, L., Pohjolainen, S., Mishev, A., Reiner, M., Lee, J., Laitinen, T., Didkovsky, L., Pizzo, V., Kim, R., Klassen, A., Karlicky, M., Cho, K., Gary, D., Usoskin, I., Valtonen, E., Vainio, R. (2017) Investigating the Origins of Two Extreme Solar Particle Events: Proton Source Profile and Associated Electromagnetic Emissions. Astrophysical Journal, 839 (2), 79. doi:10.3847/1538-4357/aa6a13

Investigating the origins of two extreme solar particle events : proton source profile and associated electromagnetic emissions

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Author: Kocharov, Leon1; Pohjolainen, Silja2; Mishev, Alexander3;
Organizations: 1Sodankylä Geophysical Observatory/Oulu Unit, University of Oulu, P.O.B. 3000, Oulu FI-90014, Finland
2Tuorla Observatory, University of Turku, Piikkiö FI-21500, Finland
3Space Climate Research Unit, University of Oulu, Oulu FI-90014, Finland
4The Catholic University of America, Washington, DC, and NASA/Goddard Space Flight Center, Greenbelt, MD, USA
5Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea
6Center for Solar-Terrestrial Research, New Jersey Institute of Technology, Newark NJ 07102-1982, USA
7Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE, UK
8University of Southern California Space Sciences Center, 835 Bloom Walk, Los Angeles CA 90089, USA
9NOAA Space Weather Prediction Center, Boulder, CO 80305, USA
10Korea Astronomy and Space Science Institute, Daejeon 305-348, Korea
11Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität, Kiel D-24118, Germany
12Astronomical Institute of the Czech Academy of Sciences, Fričova 258, Ondřejov 251 65, Czech Republic
13University of Science and Technology, Daejeon 305-348, Korea
14Space Research Laboratory, University of Turku, Turku FI-20014, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 7.9 MB)
Persistent link:
Language: English
Published: IOP Publishing, 2017
Publish Date: 2017-04-20


We analyze the high-energy particle emission from the Sun in two extreme solar particle events in which protons are accelerated to relativistic energies and can cause a significant signal even in the ground-based particle detectors. Analysis of a relativistic proton event is based on modeling of the particle transport and interaction, from a near-Sun source through the solar wind and the Earth’s magnetosphere and atmosphere to a detector on the ground. This allows us to deduce the time profile of the proton source at the Sun and compare it with observed electromagnetic emissions. The 1998 May 2 event is associated with a flare and a coronal mass ejection (CME), which were well observed by the Nançay Radioheliograph, thus the images of the radio sources are available. For the 2003 November 2 event, the low corona images of the CME liftoff obtained at the Mauna Loa Solar Observatory are available. Those complementary data sets are analyzed jointly with the broadband dynamic radio spectra, EUV images, and other data available for both events. We find a common scenario for both eruptions, including the flare’s dual impulsive phase, the CME-launch-associated decimetric-continuum burst, and the late, low-frequency type III radio bursts at the time of the relativistic proton injection into the interplanetary medium. The analysis supports the idea that the two considered events start with emission of relativistic protons previously accelerated during the flare and CME launch, then trapped in large-scale magnetic loops and later released by the expanding CME.

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Series: Astrophysical journal
ISSN: 0004-637X
ISSN-E: 1538-4357
ISSN-L: 0004-637X
Volume: 839
Issue: 2
DOI: 10.3847/1538-4357/aa6a13
Type of Publication: A1 Journal article – refereed
Field of Science: 115 Astronomy and space science
Funding: This research was supported by the Academy of Finland through projects 260596, 258963, and 272157. A.K. was supported by the German DLR under grant 50 OC 1302. J.L. was supported by the BK21 Plus Program (21A20131111123) funded by the Ministry of Education (MOE, Korea) and National Research Foundation of Korea (NRF). M.K. acknowledges support from Grant P209/12/0103 of the Grant Agency of the Czech Republic. SOHO is a project of international cooperation between ESA and NASA.
Academy of Finland Grant Number: 260596
Detailed Information: 260596 (Academy of Finland Funding decision)
258963 (Academy of Finland Funding decision)
272157 (Academy of Finland Funding decision)
Copyright information: © 2017. The American Astronomical Society. All rights reserved.