On the Association Between Loop Prominences and Flares.

Bruzek, A.

doi:10.1086/147969

Cited by 140 publications

(63 citation statements)

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“…At intermediate time scales, there may be other time scales involved. For example, the "two-ribbon flare" paradigm was known from early Hα observations to involve the apparent growth of "loop prominence systems" (e.g., Bruzek 1964) or "sporadic coronal condensations", to use some archaic terminology. We now recognize this apparent growth as a cooling process, in that the flare itself creates higher-temperature plasmas initially (see Sect.…”

Section: Energy Buildup and Releasementioning

confidence: 99%

Global Properties of Solar Flares

2011

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This article broadly reviews our knowledge of solar flares. There is a particular focus on their global properties, as opposed to the microphysics such as that needed for magnetic reconnection or particle acceleration as such. Indeed solar flares will always remain in the domain of remote sensing, so we cannot observe the microscales directly and must understand the basic physics entirely via the global properties plus theoretical inference. The global observables include the general energetics-radiation in flares and mass loss in coronal mass ejections (CMEs)-and the formation of different kinds of ejection and global wave disturbance: the type II radio-burst exciter, the Moreton wave, the EIT "wave", and the "sunquake" acoustic waves in the solar interior. Flare radiation and CME kinetic energy can have comparable magnitudes, of order 10 32 erg each for an X-class event, with the bulk of the radiant energy in the visible-UV continuum. We argue that the impulsive phase of the flare dominates the energetics of all of these manifestations, and also point out that energy and momentum in this phase largely reside in the electromagnetic field, not in the observable plasma.

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Section: Energy Buildup and Releasementioning

confidence: 99%

Global Properties of Solar Flares

2011

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“…As the flare evolves, the two ribbons extend around the sheared PIL, which is observed in Hα and other chromospheric lines (e.g., Dodson 1949;Bruzek 1964;Asai et al 2004). In the standard model for eruptive flares, the CSHKP model (Carmichael 1964;Sturrock 1966;Hirayama 1974;Kopp & Pneuman 1976), the flare ribbons are caused by magnetic reconnection through the precipitation of high-energy electrons and the effect of thermal conduction, and thus they indicate the footpoints of newly reconnected field lines (post-flare loops).…”

Section: Introductionmentioning

confidence: 99%

Magnetic Properties of Solar Active Regions That Govern Large Solar Flares and Eruptions

Toriumi

Schrijver

Harra³

et al. 2017

ApJ

166

123

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Solar flares and coronal mass ejections (CMEs), especially the larger ones, emanate from active regions (ARs). With the aim to understand the magnetic properties that govern such flares and eruptions, we systematically survey all flare events with GOES levels of ≥ M5.0 within 45• from disk center between May 2010 and April 2016. These criteria lead to a total of 51 flares from 29 ARs, for which we analyze the observational data obtained by the Solar Dynamics Observatory. More than 80% of the 29 ARs are found to exhibit δ-sunspots and at least three ARs violate Hale's polarity rule. The flare durations are approximately proportional to the distance between the two flare ribbons, to the total magnetic flux inside the ribbons, and to the ribbon area. From our study, one of the parameters that clearly determine whether a given flare event is CME-eruptive or not is the ribbon area normalized by the sunspot area, which may indicate that the structural relationship between the flaring region and the entire AR controls CME productivity. AR characterization show that even X-class events do not require δ-sunspots or strong-field, high-gradient polarity inversion lines. An investigation of historical observational data suggests the possibility that the largest solar ARs, with magnetic flux of 2×10 23 Mx, might be able to produce "superflares" with energies of order of 10 34 erg. The proportionality between the flare durations and magnetic energies is consistent with stellar flare observations, suggesting a common physical background for solar and stellar flares.

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“…The proton-flare active regions are not randomly distributed on the solar disk, but they tend to occur in complexes of activity which stay on the solar surface for many months and even years. Attention is called to the peculiar clustering of proton-flare regions on the Southern hemisphere, where two sources of activity, at a longitudinal distance of about 180°, seemed to move on the solar disk between 1956 and 1962 opposite to the solar rotation, shifting in the longitude at about 70 heliographic degrees per 10 solar rotations.In my contribution, I would like to discuss very briefly two problems -the oc currence of loop-prominence systems in active regions which produce proton flares, and the occurrence of such proton-flare active regions in complexes of activity.In 1964, Bruzek called attention to the fact that all loop-prominence systems observed on the disk were associated with proton flares, and he concluded that this association of loop-prominence systems with proton flares was a general character istic of these two active phenomena (Bruzek, 1964).We have tried to verify this conclusion of Bruzek using the catalogue of flares associated with type-IV radio bursts prepared by Olmr and myself (1966). This catalogue, containing 174 events, can also be considered for a list of proton flares which appeared on the Sun from 1956 to 1963, and we compared it with 65 loopprominence system occurrences, taken from lists prepared by Bruzek (1964) and Kleczek (1967).…”

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confidence: 90%

“…In 1964, Bruzek called attention to the fact that all loop-prominence systems observed on the disk were associated with proton flares, and he concluded that this association of loop-prominence systems with proton flares was a general character istic of these two active phenomena (Bruzek, 1964).…”

Section: Introductionmentioning

confidence: 99%

“…This catalogue, containing 174 events, can also be considered for a list of proton flares which appeared on the Sun from 1956 to 1963, and we compared it with 65 loopprominence system occurrences, taken from lists prepared by Bruzek (1964) and Kleczek (1967). We have verified that all 24 loop-prominence systems observed on the disk were preceded by proton flares listed in the catalogue, in full agreement with Bruzek's results.…”

Section: Introductionmentioning

confidence: 99%

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Loop-prominence systems and proton-flare active regions

Švestka

1968

Symp. - Int. Astron. Union

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It is shown that proton flares and loop-prominence systems form in the same type of active regions. Quite often both these phenomena appear simultaneously, but there are also many cases, when only the proton flare or only the loop-prominence system fully develops. The proton-flare active regions are not randomly distributed on the solar disk, but they tend to occur in complexes of activity which stay on the solar surface for many months and even years. Attention is called to the peculiar clustering of proton-flare regions on the Southern hemisphere, where two sources of activity, at a longitudinal distance of about 180°, seemed to move on the solar disk between 1956 and 1962 opposite to the solar rotation, shifting in the longitude at about 70 heliographic degrees per 10 solar rotations.In my contribution, I would like to discuss very briefly two problems -the oc currence of loop-prominence systems in active regions which produce proton flares, and the occurrence of such proton-flare active regions in complexes of activity.In 1964, Bruzek called attention to the fact that all loop-prominence systems observed on the disk were associated with proton flares, and he concluded that this association of loop-prominence systems with proton flares was a general character istic of these two active phenomena (Bruzek, 1964).We have tried to verify this conclusion of Bruzek using the catalogue of flares associated with type-IV radio bursts prepared by Olmr and myself (1966). This catalogue, containing 174 events, can also be considered for a list of proton flares which appeared on the Sun from 1956 to 1963, and we compared it with 65 loopprominence system occurrences, taken from lists prepared by Bruzek (1964) and Kleczek (1967). We have verified that all 24 loop-prominence systems observed on the disk were preceded by proton flares listed in the catalogue, in full agreement with Bruzek's results. Of course, one must not forget that Bruzek tried to find loop promi nences in this type of flares and, therefore, he might perhaps have missed some other events. For the limb-prominence systems the situation is quite different. Only 9 events of the 40 observed limb systems were clearly preceded by proton flares. It is true that, due to the directional sensitivity at long wavelengths, the classification of type-IV bursts for flares close to the limb is difficult, but one can hardly believe that we could have missed 31 type-IV bursts out of the total number of 40. And this is also sup ported by the fact that 14 events of these loop-prominence systems were observed on the Western solar limb without any PCA effect, which accompanies the proton flares

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On the Association Between Loop Prominences and Flares.

Cited by 140 publications

References 0 publications

Global Properties of Solar Flares

Global Properties of Solar Flares

Magnetic Properties of Solar Active Regions That Govern Large Solar Flares and Eruptions

Loop-prominence systems and proton-flare active regions

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