Flare Energetics

Wu, Si; Jager, C. de; Dennis, B. R.; Hudson, H. S.; Simnett, G. M.; Strong, K. T.; Bentley, R. D.; Bornmann, P. L.; Bruner, M. E.; Cargill, P. J.; Crannell, C. J.; Doyle, J. G.; Hyder, C. L.; Kopp, R. A.; Lemen, J. R.; Martin, Sara; Pallavicini, R.; Peres, G.; Serio, S.; Sylwester, J.; Veck, N. J.

doi:10.1007/978-94-009-2331-7_5

Cited by 4 publications

(3 citation statements)

References 139 publications

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“…Canfield et al, 1980;Wu et al, 1986;Emslie et al, 2012). The first is non-thermal energy, observed through hard X-ray and gamma-ray emission, the second is thermal emission, observed through heating of the plasma, and the last is via the bulk motion observed if there is an ejection or CME.…”

Section: Do X-flares With No Eruptions Have More Non-thermal Energy?mentioning

confidence: 99%

The Characteristics of Solar X-Class Flares and CMEs: A Paradigm for Stellar Superflares and Eruptions?

et al. 2016

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This paper explores the characteristics of 42 solar X-class flares that were observed between February 2011 and November 2014, with data from the Solar Dynamics Observatory (SDO) and other sources. This flare list includes nine X-class flares that had no associated CMEs. In particular our aim was to determine whether a clear signature could be identified to differentiate powerful flares that have coronal mass ejections (CMEs) from those that do not. Part of the motivation for this study is the characterization of the solar paradigm for flare/CME occurrence as a possible guide to the stellar observations; hence we emphasize spectroscopic signatures. To do this we ask the following questions: Do all eruptive flares have long durations? Do CME-related flares stand out in terms of active-region size vs. flare duration? Do flare magnitudes correlate with sunspot areas, and, if so, are eruptive events distinguished? Is the occurrence of CMEs related to the fraction of the activeregion area involved? Do X-class flares with no eruptions have weaker non-thermal signatures? Is the temperature dependence of evaporation different in eruptive and non-eruptive flares? Is EUV dimming only seen in eruptive flares? We find only one feature consistently associated with CME-related flares specifically: coronal dimming in lines characteristic of the quiet-Sun corona, i.e. 1 -2 MK. We do not find a correlation between flare magnitude and sunspot areas. Although challenging, it will be of importance to model dimming for stellar cases and make suitable future plans for observations in the appropriate wavelength range in order to identify stellar CMEs consistently.

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Section: Do X-flares With No Eruptions Have More Non-thermal Energy?mentioning

confidence: 99%

The Characteristics of Solar X-Class Flares and CMEs: A Paradigm for Stellar Superflares and Eruptions?

et al. 2016

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“…The flare (electromagnetic) and the CME (mass motions) contain the bulk of the energy released, but in both cases, the observations are incomplete at best. Recently Emslie et al (2012) attempted a general description of the event energy partitioning (see also Canfield et al (1980) and Webb et al (1980) for Skylab-based studies and Wu et al (1986) for the Solar Maximum Mission results). The modern data suggest that the total CME energy may exceed that of the radiation in major flare/CME events.…”

Section: Event Energy Partitionmentioning

confidence: 99%

Extreme Solar Events: Setting up a Paradigm

Usoskin,

Miyake,

Baroni

et al. 2023

Space Sci Rev

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The Sun is magnetically active and often produces eruptive events on different energetic and temporal scales. Until recently, the upper limit of such events was unknown and believed to be roughly represented by direct instrumental observations. However, two types of extreme events were discovered recently: extreme solar energetic particle events on the multi-millennial time scale and super-flares on sun-like stars. Both discoveries imply that the Sun might rarely produce events, called extreme solar events (ESE), whose energy could be orders of magnitude greater than anything we have observed during recent decades. During the years following these discoveries, great progress has been achieved in collecting observational evidence, uncovering new events, making statistical analyses, and developing theoretical modelling. The ESE paradigm lives and is being developed. On the other hand, many outstanding questions still remain open and new ones emerge. Here we present an overview of the current state of the art and the forming paradigm of ESE from different points of view: solar physics, stellar–solar projections, cosmogenic-isotope data, modelling, historical data, as well as terrestrial, technological and societal effects of ESEs. Special focus is paid to open questions and further developments. This review is based on the joint work of the International Space Science Institute (ISSI) team #510 (2020–2022).

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“…Corrections for contamination by neighboring lines does not significantly decrease these differences [ Bhatia et al , 1989]. These high densities suggest that the flare volume is not uniformly filled and that substantial filling factors are required ( e. g. Wu et al , 1986; Linford and Wolfson , 1988].…”

Section: Energy Decay: the Decay Phasementioning

confidence: 99%

Solar X‐Ray Physics

Bornmann

1991

Reviews of Geophysics

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This is a review of the research in solar x‐ray phenomena that has been done by American scientists in the last four years. This research ranges from new instrumentation, such as multilayer mirrors and high spectral resolution detectors, to refined theories and observations of the flare process. Contributions have been made in our understanding of x‐ray bright points, solar active regions, solar flares, and flare‐associated phenomena. The hard x‐ray spectra during the impulsive phase of solar flares have been examined in greater detail and found, among other things, to fit a double power law. Models for the hard x‐ray emissions have focused largely on electron acceleration by field‐aligned currents, although other models such as proton beams, waves, and neutral beams have also been investigated. Correlations between the hard x‐ray emission and radio, ultraviolet, and gamma‐ray emissions have been used to provide additional constraints on the flare models. The process known as chromospheric evaporation, which is seen as blueshifts of the soft x‐ray line profiles, has been explored through further analysis of the observations and the development of new models. New atomic calculations have been performed so that further information about the plasma properties during the decay phase of solar flares can be derived from the soft x‐ray line emissions. Spatially resolved observations have been used to identify new x‐ray features such as flaring arches and giant post‐flare arches. Other topics of investigation included the energy in solar flares and the long‐term variations in solar indices, the 155‐day periodicity of solar flares, and the distribution of flares on the solar disk. Finally, associations have been made between the solar x‐ray emission and the phenomena of coronal mass ejections and solar energetic particles, as well as the effect of this radiation on the earth's upper atmosphere.

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Flare Energetics

Cited by 4 publications

References 139 publications

The Characteristics of Solar X-Class Flares and CMEs: A Paradigm for Stellar Superflares and Eruptions?

The Characteristics of Solar X-Class Flares and CMEs: A Paradigm for Stellar Superflares and Eruptions?

Extreme Solar Events: Setting up a Paradigm

Solar X‐Ray Physics

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