Speed and Acceleration of Coronal Mass Ejections Associated with Sustained Gamma-Ray Emission Events Observed by Fermi/LAT
The sustained gamma-ray emission (SGRE) from the Sun is a prolonged enhancement of >100 MeV gamma-ray emission that extends beyond the flare impulsive phase. The origin of the >300 MeV protons resulting in SGRE is debated, with both flares and shocks driven by coronal mass ejections (CMEs) bei...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
| Subjects: | |
| Online Access: | https://doi.org/10.3847/1538-4357/ace627 |
| _version_ | 1827828278948265984 |
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| author | Pertti Mäkelä Nat Gopalswamy Sachiko Akiyama Hong Xie Seiji Yashiro |
| author_facet | Pertti Mäkelä Nat Gopalswamy Sachiko Akiyama Hong Xie Seiji Yashiro |
| author_sort | Pertti Mäkelä |
| collection | DOAJ |
| description | The sustained gamma-ray emission (SGRE) from the Sun is a prolonged enhancement of >100 MeV gamma-ray emission that extends beyond the flare impulsive phase. The origin of the >300 MeV protons resulting in SGRE is debated, with both flares and shocks driven by coronal mass ejections (CMEs) being the suggested sites of proton acceleration. We compared the near-Sun acceleration and space speed of CMEs with “Prompt” and “Delayed” (SGRE) gamma-ray components. We found that “Delayed”-component-associated CMEs have higher initial accelerations and space speeds than “Prompt Only”-component-associated CMEs. We selected halo CMEs (HCMEs) associated with type II radio bursts (shock-driving HCMEs) and compared the average acceleration and space speed between HCME populations with or without SGRE events, major solar energetic particle (SEP) events, metric, or decameter-hectometric (DH) type II radio bursts. We found that the SGRE-producing HCMEs associated with a DH type II radio burst and/or a major SEP event have higher space speeds and especially initial accelerations than those without an SGRE event. We estimated the radial distances and speeds of the CME-driven shocks at the end time of the 2012 January 23 and March 7 SGRE events using white-light images of STEREO Heliospheric Imagers and radio dynamic spectra of Wind WAVES. The shocks were at the radial distances of 0.6–0.8 au and their speeds were high enough (≈975 km s ^−1 and ≈750 km s ^−1 , respectively) for high-energy particle acceleration. Therefore, we conclude that our findings support the CME-driven shock as the source of >300 MeV protons. |
| first_indexed | 2024-03-12T03:47:47Z |
| format | Article |
| id | doaj.art-baa9dea7d51c4b30a495abd5ee7d3135 |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:47:47Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-baa9dea7d51c4b30a495abd5ee7d31352023-09-03T12:38:16ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-0195417910.3847/1538-4357/ace627Speed and Acceleration of Coronal Mass Ejections Associated with Sustained Gamma-Ray Emission Events Observed by Fermi/LATPertti Mäkelä0https://orcid.org/0000-0002-8182-4559Nat Gopalswamy1https://orcid.org/0000-0001-5894-9954Sachiko Akiyama2https://orcid.org/0000-0002-7281-1166Hong Xie3https://orcid.org/0000-0002-0058-1162Seiji Yashiro4https://orcid.org/0000-0002-6965-3785The Catholic University of America , 620 Michigan Avenue, N.E. Washington, DC 20064, USA ; pertti.makela@nasa.gov, makela@cua.edu; NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USANASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USAThe Catholic University of America , 620 Michigan Avenue, N.E. Washington, DC 20064, USA ; pertti.makela@nasa.gov, makela@cua.edu; NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USAThe Catholic University of America , 620 Michigan Avenue, N.E. Washington, DC 20064, USA ; pertti.makela@nasa.gov, makela@cua.edu; NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USAThe Catholic University of America , 620 Michigan Avenue, N.E. Washington, DC 20064, USA ; pertti.makela@nasa.gov, makela@cua.edu; NASA Goddard Space Flight Center , 8800 Greenbelt Road, Greenbelt, MD 20771, USAThe sustained gamma-ray emission (SGRE) from the Sun is a prolonged enhancement of >100 MeV gamma-ray emission that extends beyond the flare impulsive phase. The origin of the >300 MeV protons resulting in SGRE is debated, with both flares and shocks driven by coronal mass ejections (CMEs) being the suggested sites of proton acceleration. We compared the near-Sun acceleration and space speed of CMEs with “Prompt” and “Delayed” (SGRE) gamma-ray components. We found that “Delayed”-component-associated CMEs have higher initial accelerations and space speeds than “Prompt Only”-component-associated CMEs. We selected halo CMEs (HCMEs) associated with type II radio bursts (shock-driving HCMEs) and compared the average acceleration and space speed between HCME populations with or without SGRE events, major solar energetic particle (SEP) events, metric, or decameter-hectometric (DH) type II radio bursts. We found that the SGRE-producing HCMEs associated with a DH type II radio burst and/or a major SEP event have higher space speeds and especially initial accelerations than those without an SGRE event. We estimated the radial distances and speeds of the CME-driven shocks at the end time of the 2012 January 23 and March 7 SGRE events using white-light images of STEREO Heliospheric Imagers and radio dynamic spectra of Wind WAVES. The shocks were at the radial distances of 0.6–0.8 au and their speeds were high enough (≈975 km s ^−1 and ≈750 km s ^−1 , respectively) for high-energy particle acceleration. Therefore, we conclude that our findings support the CME-driven shock as the source of >300 MeV protons.https://doi.org/10.3847/1538-4357/ace627Solar gamma-ray emissionSolar coronal mass ejectionsSolar energetic particles |
| spellingShingle | Pertti Mäkelä Nat Gopalswamy Sachiko Akiyama Hong Xie Seiji Yashiro Speed and Acceleration of Coronal Mass Ejections Associated with Sustained Gamma-Ray Emission Events Observed by Fermi/LAT The Astrophysical Journal Solar gamma-ray emission Solar coronal mass ejections Solar energetic particles |
| title | Speed and Acceleration of Coronal Mass Ejections Associated with Sustained Gamma-Ray Emission Events Observed by Fermi/LAT |
| title_full | Speed and Acceleration of Coronal Mass Ejections Associated with Sustained Gamma-Ray Emission Events Observed by Fermi/LAT |
| title_fullStr | Speed and Acceleration of Coronal Mass Ejections Associated with Sustained Gamma-Ray Emission Events Observed by Fermi/LAT |
| title_full_unstemmed | Speed and Acceleration of Coronal Mass Ejections Associated with Sustained Gamma-Ray Emission Events Observed by Fermi/LAT |
| title_short | Speed and Acceleration of Coronal Mass Ejections Associated with Sustained Gamma-Ray Emission Events Observed by Fermi/LAT |
| title_sort | speed and acceleration of coronal mass ejections associated with sustained gamma ray emission events observed by fermi lat |
| topic | Solar gamma-ray emission Solar coronal mass ejections Solar energetic particles |
| url | https://doi.org/10.3847/1538-4357/ace627 |
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