X-Ray/Radio Quasiperiodic Pulsations Associated with Plasmoids in Solar Flare Current Sheets
Plasmoids (or magnetic islands) are believed to play an important role in the onset of fast magnetic reconnection and particle acceleration during solar flares and eruptions. Direct imaging of flare current sheets and the formation/ejection of multiple plasmoids in extreme-ultraviolet images, along...
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2025-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ada293 |
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| author | Pankaj Kumar Judith T. Karpen Joel T. Dahlin |
| author_facet | Pankaj Kumar Judith T. Karpen Joel T. Dahlin |
| author_sort | Pankaj Kumar |
| collection | DOAJ |
| description | Plasmoids (or magnetic islands) are believed to play an important role in the onset of fast magnetic reconnection and particle acceleration during solar flares and eruptions. Direct imaging of flare current sheets and the formation/ejection of multiple plasmoids in extreme-ultraviolet images, along with simultaneous X-ray and radio observations, offers significant insights into the mechanisms driving particle acceleration in solar flares. Here, we present direct imaging of the formation and ejection of multiple plasmoids in flare plasma/current sheets and the associated quasiperiodic pulsations (QPPs) observed at X-ray and radio wavelengths, using observations from the Solar Dynamics Observatory/Atmospheric Imaging Assembly, RHESSI, and the Fermi Gamma-ray Burst Monitor. These plasmoids propagate bidirectionally upward and downward along the flare current sheet beneath the erupting flux rope during two successive flares associated with confined/failed eruptions. The flux rope exhibits evidence of helical kink instability, with the formation and ejection of multiple plasmoids in the flare current sheet, as predicted in an MHD simulation of a kink-unstable flux rope. RHESSI X-ray images show double coronal sources (“looptop” and higher coronal sources) located at both ends of the flare current/plasma sheet. Moreover, we detect an additional transient faint X-ray source (6–12 keV) located between the double coronal sources, which is cospatial with multiple plasmoids in the flare current sheet. X-ray (soft and hard) and radio (decimetric) observations unveil QPPs (periods ≈ 10 s and 100 s) associated with the ejection and coalescence of plasmoids. These observations suggest that energetic electrons are accelerated during the ejection and coalescence of multiple plasmoids in the flare current sheet. |
| format | Article |
| id | doaj-art-8ebdeb283fa54f4baba276d780994fcc |
| institution | Kabale University |
| issn | 1538-4357 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | IOP Publishing |
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| series | The Astrophysical Journal |
| spelling | doaj-art-8ebdeb283fa54f4baba276d780994fcc2025-02-11T15:58:20ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-01980215810.3847/1538-4357/ada293X-Ray/Radio Quasiperiodic Pulsations Associated with Plasmoids in Solar Flare Current SheetsPankaj Kumar0https://orcid.org/0000-0001-6289-7341Judith T. Karpen1https://orcid.org/0000-0002-6975-5642Joel T. Dahlin2https://orcid.org/0000-0002-9493-4730Department of Physics, American University , Washington, DC 20016, USA ; pankaj.kumar@nasa.gov; Heliophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USAHeliophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USAHeliophysics Science Division, NASA Goddard Space Flight Center , Greenbelt, MD 20771, USA; Astronomy Department, University of Maryland , College Park, MD 20742, USAPlasmoids (or magnetic islands) are believed to play an important role in the onset of fast magnetic reconnection and particle acceleration during solar flares and eruptions. Direct imaging of flare current sheets and the formation/ejection of multiple plasmoids in extreme-ultraviolet images, along with simultaneous X-ray and radio observations, offers significant insights into the mechanisms driving particle acceleration in solar flares. Here, we present direct imaging of the formation and ejection of multiple plasmoids in flare plasma/current sheets and the associated quasiperiodic pulsations (QPPs) observed at X-ray and radio wavelengths, using observations from the Solar Dynamics Observatory/Atmospheric Imaging Assembly, RHESSI, and the Fermi Gamma-ray Burst Monitor. These plasmoids propagate bidirectionally upward and downward along the flare current sheet beneath the erupting flux rope during two successive flares associated with confined/failed eruptions. The flux rope exhibits evidence of helical kink instability, with the formation and ejection of multiple plasmoids in the flare current sheet, as predicted in an MHD simulation of a kink-unstable flux rope. RHESSI X-ray images show double coronal sources (“looptop” and higher coronal sources) located at both ends of the flare current/plasma sheet. Moreover, we detect an additional transient faint X-ray source (6–12 keV) located between the double coronal sources, which is cospatial with multiple plasmoids in the flare current sheet. X-ray (soft and hard) and radio (decimetric) observations unveil QPPs (periods ≈ 10 s and 100 s) associated with the ejection and coalescence of plasmoids. These observations suggest that energetic electrons are accelerated during the ejection and coalescence of multiple plasmoids in the flare current sheet.https://doi.org/10.3847/1538-4357/ada293Solar magnetic reconnectionSolar coronaSolar flaresSolar coronal mass ejections |
| spellingShingle | Pankaj Kumar Judith T. Karpen Joel T. Dahlin X-Ray/Radio Quasiperiodic Pulsations Associated with Plasmoids in Solar Flare Current Sheets The Astrophysical Journal Solar magnetic reconnection Solar corona Solar flares Solar coronal mass ejections |
| title | X-Ray/Radio Quasiperiodic Pulsations Associated with Plasmoids in Solar Flare Current Sheets |
| title_full | X-Ray/Radio Quasiperiodic Pulsations Associated with Plasmoids in Solar Flare Current Sheets |
| title_fullStr | X-Ray/Radio Quasiperiodic Pulsations Associated with Plasmoids in Solar Flare Current Sheets |
| title_full_unstemmed | X-Ray/Radio Quasiperiodic Pulsations Associated with Plasmoids in Solar Flare Current Sheets |
| title_short | X-Ray/Radio Quasiperiodic Pulsations Associated with Plasmoids in Solar Flare Current Sheets |
| title_sort | x ray radio quasiperiodic pulsations associated with plasmoids in solar flare current sheets |
| topic | Solar magnetic reconnection Solar corona Solar flares Solar coronal mass ejections |
| url | https://doi.org/10.3847/1538-4357/ada293 |
| work_keys_str_mv | AT pankajkumar xrayradioquasiperiodicpulsationsassociatedwithplasmoidsinsolarflarecurrentsheets AT judithtkarpen xrayradioquasiperiodicpulsationsassociatedwithplasmoidsinsolarflarecurrentsheets AT joeltdahlin xrayradioquasiperiodicpulsationsassociatedwithplasmoidsinsolarflarecurrentsheets |