Invited Review: Short-term Variability with the Observations from the Helioseismic and Magnetic Imager (HMI) Onboard the Solar Dynamics Observatory (SDO): Insights into Flare Magnetism

Kazachenko, Maria D.; Corchado-Albelo, Marcel F.; Tamburri, C. A.; Welsch, B. T.

doi:10.1007/s11207-022-01987-6

Cited by 17 publications

(15 citation statements)

References 151 publications

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“…Frequently, strong flares are accompanied by coronal mass ejection (CME), releasing a large amount of radiation that may have severe space-weather impacts (Schrijver 2015). Therefore, understanding the real mechanism behind explosive events like solar flares and CMEs has become one of the hot topics in solar physics research (Benz 2008;Kazachenko et al 2022a).…”

Section: Introductionmentioning

confidence: 99%

A Statistical Analysis of Magnetic Field Changes in the Photosphere during Solar Flares Using High-cadence Vector Magnetograms and Their Association with Flare Ribbons

Yadav

Kazachenko

2023

ApJ

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We analyze high-cadence vector magnetograms (135 s) and flare-ribbon observations of 37 flares from the Solar Dynamics Observatory to understand the spatial and temporal properties of changes in the photospheric vector magnetic field and their relationship to footpoints of reconnected fields. Confirming previous studies, we find that the largest permanent changes in the horizontal field component lie near the polarity inversion line, whereas changes in the vertical field are less pronounced and are distributed throughout the active region. We find that pixels swept up by ribbons do not always exhibit permanent changes in the field. However, when they do, ribbon emission typically occurs several minutes before the start time of field changes. The changes in the properties of the field show no relation to the size of active regions, but are strongly related to the flare-ribbon properties such as ribbon magnetic flux and ribbon area. For the first time, we find that the duration of permanent changes in the field is strongly coupled with the duration of the flare, lasting on average 29% of the duration of the GOES flare. Our results suggest that changes in photospheric magnetic fields are caused by a combination of two scenarios: contraction of flare loops driven by magnetic reconnection and coronal implosion.

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Section: Introductionmentioning

confidence: 99%

A Statistical Analysis of Magnetic Field Changes in the Photosphere during Solar Flares Using High-cadence Vector Magnetograms and Their Association with Flare Ribbons

Yadav

Kazachenko

2023

ApJ

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“…However, again comparing statistics of confined and CME-associated flares, recent investigations have shown the importance of threshold (Liokati et al 2022) or intrinsic magnetic-flux-normalized (Gupta et al 2021;Li et al 2022) AR magnetic energies and helicities in overcoming the background field restrictions to produce CMEs. Kazachenko et al (2022) review further characteristic details for distinguishing between confined and CME-associated flares. A potential tool in determining which ARs may produce predominately noneruptive flares could be enhanced whitelight emission from strong high coronal magnetic fields confining any eruptions from an AR.…”

Section: Eruptive Versus Noneruptive Flaresmentioning

confidence: 99%

Solar–Stellar Connection: X-Ray Flares to Energetic (E > 10 MeV) Particle Events

Kahler,

Ling

2023

ApJ

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Energetic particle environments are an important factor for the viability of life on exoplanets surrounding flare stars. In the heliosphere, large gradual solar energetic (E > 10 MeV) particle (SEP) events are produced by shocks from fast coronal mass ejections (CMEs). Extensive observations of solar X-ray flares, CMEs, and SEP events can provide guidance for flare star models of stellar energetic particle (StEP) events, for which stellar flares, but only rarely the associated CMEs, are observed. Comparing an extensive list of peak fluxes, timescales, and peak temperatures of 585 ≥ M3.0 solar X-ray flares with the occurrence of associated SEP events of peak flux Ip > 1.4 proton flux units, enhanced with proxy decametric–hectometric type II radio bursts, we determine guidelines for StEP event outcomes, given only stellar X-ray flare inputs. Longer timescales and lower peak temperatures of X-ray flares with a given peak X-ray flux Fp are more favorable for occurrence of associated SEP/StEP events, which, however, are only a minority of all solar flare outcomes. Most solar flares do not result in SEP events, invalidating scaling laws between stellar flares, CMEs, and StEP events. We discuss recent observations and models of the flare–CME relationship and suggest that StEP intensities Ip may often be overestimated.

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“…Below we review some magnetic field properties quantified in confined and eruptive events from observations. For more details on recent statistical studies of flare magnetic properties, we recommend reading our recent review paper (Kazachenko et al 2022a).…”

Section: Introductionmentioning

confidence: 99%

A Database of Magnetic and Thermodynamic Properties of Confined and Eruptive Solar Flares

Kazachenko

2023

ApJ

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Solar flares sometimes lead to coronal mass ejections that directly affect Earth's environment. However, a large fraction of flares, including on solar-type stars, are confined flares. What are the differences in physical properties between confined and eruptive flares? For the first time, we quantify the thermodynamic and magnetic properties of hundreds of confined and eruptive flares of GOES class C5.0 and above, 480 flares in total. We first analyze large flares of GOES class M1.0 and above observed by the Solar Dynamics Observatory, 216 flares in total, including 103 eruptive and 113 confined flares, from 2010 until 2016 April; we then look at the entire data set of 480 flares above class C5.0. We compare GOES X-ray thermodynamic flare properties, including peak temperature and emission measure, and active-region (AR) and flare-ribbon magnetic field properties, including reconnected magnetic flux and peak reconnection rate. We find that for fixed peak X-ray flux, confined and eruptive flares have similar reconnection fluxes; however, for fixed peak X-ray flux confined flares have on average larger peak magnetic reconnection rates, are more compact, and occur in larger ARs than eruptive flares. These findings suggest that confined flares are caused by reconnection between more compact, stronger, lower-lying magnetic fields in larger ARs that reorganizes a smaller fraction of these regions’ fields. This reconnection proceeds at faster rates and ends earlier, potentially leading to more efficient flare particle acceleration in confined flares.

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Invited Review: Short-term Variability with the Observations from the Helioseismic and Magnetic Imager (HMI) Onboard the Solar Dynamics Observatory (SDO): Insights into Flare Magnetism

Cited by 17 publications

References 151 publications

A Statistical Analysis of Magnetic Field Changes in the Photosphere during Solar Flares Using High-cadence Vector Magnetograms and Their Association with Flare Ribbons

A Statistical Analysis of Magnetic Field Changes in the Photosphere during Solar Flares Using High-cadence Vector Magnetograms and Their Association with Flare Ribbons

Solar–Stellar Connection: X-Ray Flares to Energetic (E > 10 MeV) Particle Events

A Database of Magnetic and Thermodynamic Properties of Confined and Eruptive Solar Flares

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