Erratum: “Why Is the Great Solar Active Region 12192 Flare-rich but CME-poor?” (2015, ApJL, 804, L28)

Sun, Xudong; Bobra, Monica; Hoeksema, J. T.; Liu, Y.; Li, Yan; Shen, Chenglong; Couvidat, S.; Norton, A. A.; Fisher, G. H.

doi:10.3847/2041-8213/aa9b2a

Cited by 141 publications

(238 citation statements)

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“…Due to hosting the largest sunspot group since 1990, AR 12192 observed in 2014 October has been paid significant attention (e.g., Sun et al 2015;Thalmann et al 2015). According to the statistics by Chen et al (2015), while AR 12192 passed across the visible solar disk from October18 to 29, it produced 6 X-class and 29 M-class flares.…”

Section: Overview Of Ar 12192mentioning

confidence: 99%

“…Thalmann et al (2015) provided evidence for repeated energy release, indicating that the same magnetic field structures were repeatedly involved in magnetic reconnection. Sun et al (2015) studied the magnetic conditions of the AR and suggested that the magnetic non-potentiality over the restriction of background field limited the eruptions. Photospheric motions of emerged magnetic fluxes lead to shearing the associated coronal magnetic field, which then yields a tether-cutting favorable configuration .…”

Section: Overview Of Ar 12192mentioning

confidence: 99%

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Are Complex Magnetic Field Structures Responsible for the Confined X-class Flares in Super Active Region 12192?

Zhang

Chen

2017

ApJ

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From 2014 October 19 to 27, six X-class flares occurred in super active region (AR) 12192. They were all confined flares and were not followed by coronal mass ejections (CMEs). To examine the structures of the four flares close to the solar disk center from October 22 to 26, we employ firstly composite tripletime images in each flare process to display the stratified structure of these flare loops. The loop structures of each flare in both lower (171Å) and higher (131Å) temperature channels are complex, e.g., the flare loops rooting at flare ribbons are sheared or twisted (enwound) together, and the complex structures have not been destroyed during the flares. For the first flare, although the flare loop system appears as a spindle shape, we can estimate their structure from observations, with lengths ranging from 130 to 300 Mm, heights from 65 to 150 Mm, widths at the middle part of the spindle from 40 to 100 Mm, and shear angles from 16• to 90• . Moreover, the flare ribbons display irregular movements, such as the left ribbon fragments of the flare on 22 swept a small region repeatedly, and the both ribbons of the flare on 26 moved along the same direction, instead of separating from each other. These irregular movements also imply that the corresponding flare loops are complex, e.g. several sets of flare loops are twisted together. Although previous studies suggest that the background magnetic fields prevent confined flares from erupting, we firstly suggest based on these observations that the complex flare loop structures may be responsible for these confined flares.

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Section: Overview Of Ar 12192mentioning

confidence: 99%

Section: Overview Of Ar 12192mentioning

confidence: 99%

Are Complex Magnetic Field Structures Responsible for the Confined X-class Flares in Super Active Region 12192?

Zhang

Chen

2017

ApJ

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“…There were another 29 M-class flares of which only one, originating from the periphery of the region (where five other M flares occurred), was associated with a CME . See Sun et al (2015) for further discussion and interpretation of why this region exhibits so many energetic confined flares.…”

Section: Ar 12192mentioning

confidence: 99%

The Nonpotentiality of Coronae of Solar Active Regions, the Dynamics of the Surface Magnetic Field, and the Potential for Large Flares

Schrijver

2016

ApJ

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Flares and eruptions from solar active regions (ARs) are associated with atmospheric electrical currents accompanying distortions of the coronal field away from a lowest-energy potential state. In order to better understand the origin of these currents and their role in M-and X-class flares, I review all AR observations made with Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager and SDO/Atmospheric Imaging Assembly from 2010 May through 2014 October within ≈40°from the disk center. I select the roughly 4% of all regions that display a distinctly nonpotential coronal configuration in loops with a length comparable to the scale of the AR, and all that emit GOES X-class flares. The data for 41 regions confirm, with a single exception, that strong-field, high-gradient polarity inversion lines (SHILs) created during emergence of magnetic flux into, and related displacement within, pre-existing ARs are associated with X-class flares. Obvious nonpotentiality in the AR-scale loops occurs in six of ten selected regions with X-class flares, all with relatively long SHILs along their primary polarity inversion line, or with a long internal filament there. Nonpotentiality can exist in ARs well past the flux-emergence phase, often with reduced or absent flaring. I conclude that the dynamics of the flux involved in the compact SHILs is of pre-eminent importance for the large-flare potential of ARs within the next day, but that their associated currents may not reveal themselves in AR-scale nonpotentiality. In contrast, AR-scale nonpotentiality, which can persist for many days, may inform us about the eruption potential other than those from SHILs which is almost never associated with X-class flaring.

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“…For example, there were 164 M and X class flares on the western hemisphere in 2011-2013, and for at least 29 of these flares, the ongoing background particle intensities were low, yet no 25 MeV proton event was detected at Earth. In addition, Richardson et al (2016) discuss the low occurrence rate of 25 MeV proton events during the presence of the largest sunspot region in 24 years, in October 2014, that produced a number of confined X class flares without coronal mass ejections (Sun et al, 2015;Chen et al, 2015).…”

Section: Mev Proton Events Since 1967mentioning

confidence: 99%

25 MeV solar proton events in Cycle 24 and previous cycles

Richardson

Rosenvinge

Cane

2017

Advances in Space Research

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We summarize observations of around a thousand solar energetic particle (SEP) events since 1967 that include ∼ 25 MeV protons, made by various near-Earth spacecraft (IMPs 4, 5, 7, 8, ISEE 3, SOHO), that encompass Solar Cycle 20 to the current cycle (24). We also discuss recent observations of similar SEP events in Cycle 24 made by the STEREO spacecraft. The observations show, for example, that the time distribution of ∼ 25 MeV proton events varies from cycle to cycle. In particular, the time evolution of the SEP occurrence rate in Cycle 24 is strongly asymmetric between the northern and southern solar hemispheres, and tracks the sunspot number in each hemisphere, whereas Cycle 23 was more symmetric. There was also an absence of 25 MeV proton events during the solar minimum preceding Cycle 24 (other minima show occasional, often reasonably intense events). So far, events comparable to the exceptionally intense events detected in Cycles 22 and 23 have not been observed at Earth in Cycle 24, though Cycle 21 (the largest of the cycles considered here) also apparently lacked such events. We note a correlation between the rates of intense 25 MeV proton events and "ground level enhancements" (GLEs) observed by neutron monitors, since 1967, and conclude that the number of "official" GLEs (1) observed to date in Cycle 24 appears to be significantly lower than expected (5 to 7 ± 1) based on the rate of intense 25 MeV proton events in this cycle.

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Erratum: “Why Is the Great Solar Active Region 12192 Flare-rich but CME-poor?” (2015, ApJL, 804, L28)

Cited by 141 publications

References 0 publications

Are Complex Magnetic Field Structures Responsible for the Confined X-class Flares in Super Active Region 12192?

Are Complex Magnetic Field Structures Responsible for the Confined X-class Flares in Super Active Region 12192?

The Nonpotentiality of Coronae of Solar Active Regions, the Dynamics of the Surface Magnetic Field, and the Potential for Large Flares

25 MeV solar proton events in Cycle 24 and previous cycles

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