Multiple Sources of Solar High-energy Protons

Leon Kocharov, Nicola Omodei, Alexander Mishev, Melissa Pesce-Rollins, Francesco Longo, Sijie Yu, Dale E. Gary, Rami Vainio, Ilya Usoskin

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


During the 24th solar cycle, the Fermi Large Area Telescope (LAT) has observed a total of 27 solar flares possessing delayed γ-ray emission, including the exceptionally well-observed flare and coronal mass ejection (CME) on 2017 September 10. Based on the Fermi/LAT data, we plot, for the first time, maps of possible sources of the delayed >100 MeV γ-ray emission of the 2017 September 10 event. The long-lasting γ-ray emission is localized under the CME core. The γ-ray spectrum exhibits intermittent changes in time, implying that more than one source of high-energy protons was formed during the flare-CME eruption. We find a good statistical correlation between the γ-ray fluences of the Fermi/LAT-observed delayed events and the products of corresponding CME speed and the square root of the soft X-ray flare magnitude. Data support the idea that both flares and CMEs jointly contribute to the production of subrelativistic and relativistic protons near the Sun.

Original languageEnglish (US)
Article number12
JournalAstrophysical Journal
Issue number1
StatePublished - Jul 1 2021

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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