J/ApJ/881/1ivo://CDS.VizieR/J/ApJ/881/1doi:10.26093/cds/vizier.18810001CDSAschwanden+Aschwanden M.J.Kontar E.P.Jeffrey N.L.S.2021-12-08T21:18:26Z2021-01-06T12:23:00ZCDS support team

CDS, Observatoire de Strasbourg, 11 rue de l'Universite, F-67000 Strasbourg, France

cds-question@unistra.frsolar-systemthe-sunspectroscopyx-ray-sourcesstellar-flaresOne of the key problems in solar flare physics is the determination of the low-energy cut-off: the value that determines the energy of nonthermal electrons and hence flare energetics. We discuss different approaches to determine the low-energy cut-off in the spectrum of accelerated electrons: (I) the total electron number model, (II) the time-of-flight model (based on the equivalence of the time-of-flight and the collisional deflection time), (III) the warm target model of Kontar et al., and (IV) the model of the spectral cross-over between thermal and nonthermal components. We find that the first three models are consistent with a low-energy cutoff with a mean value of ~10keV, while the cross-over model provides an upper limit for the low-energy cutoff with a mean value of ~21keV. Combining the first three models we find that the ratio of the nonthermal energy to the dissipated magnetic energy in solar flares has a mean value of qE=0.57{+/-}0.08, which is consistent with an earlier study based on the simplified approximation of the warm target model alone (qE=0.51{+/-}0.17). This study corroborates the self-consistency between three different low-energy cutoff models in the calculation of nonthermal flare energies.2019ApJ...881....1Ahttps://cdsarc.cds.unistra.fr/viz-bin/cat/J/ApJ/881/1CatalogResearchIsServedByTAP VizieR generic servicerelated-toJ/ApJ/757/94 : Solar flares observed with GOES and AIA (Aschwanden, 2012)J/ApJ/797/50 : Global energetics of solar flares. I. (Aschwanden+, 2014)J/ApJ/802/53 : Global energetics of solar flares. II. (Aschwanden+, 2015)J/ApJ/831/105 : Global energetics of solar flares. IV. CME (Aschwanden, 2016)J/ApJ/832/27 : Global energetics of solar flares. III. (Aschwanden+, 2016)J/ApJ/833/284 : Quasi-periodic pulsations in solar flares (Inglis+, 2016)J/ApJ/845/36 : Complex network for solar active regions (Daei+, 2017)J/ApJ/847/115 : The solar flare complex network (Gheibi+, 2017)J/ApJ/851/91 : Statistical studies solar white-light flares (Namekata+, 2017)http://hesperia.gsfc.nasa.gov/ : OSPEW software homepagehttps://cds.unistra.fr/vizier-org/licences_vizier.htmlhttps://vizier.cds.unistra.fr/viz-bin/VizieR-2?-source=J/ApJ/881/1https://vizier.iucaa.in/viz-bin/VizieR-2?-source=J/ApJ/881/1http://vizieridia.saao.ac.za/viz-bin/VizieR-2?-source=J/ApJ/881/1https://vizier.cds.unistra.fr/viz-bin/votable?-source=J/ApJ/881/1https://vizier.iucaa.in/viz-bin/votable?-source=J/ApJ/881/1http://vizieridia.saao.ac.za/viz-bin/votable?-source=J/ApJ/881/1GETtext/xml+votablehttps://tapvizier.cds.unistra.fr/TAPVizieR/tapX-raydefaultJ/ApJ/881/1/table2Observables and model energies for flare hard X-ray emission in 143 M and X-class flare eventsPosHeliographic positionmeta.notecharDur[160/20740] Hard X-ray flare durationstime.durationintrecnoRecord number assigned by the VizieR team. Should Not be used for identification.meta.recordintSeq[1/395] Sequential flare event identifiermeta.id;meta.mainintObs[2010/2014] Observation year UTtime.epochObs.HObservation hour UThtime.epochintObs.minObservation minute UTmintime.epochintClGeostationary Operational Environmental Satellite (GOES) M or X-classsrc.classcharEM49[0/240.7] Emission measurecm**-3phys.emissMeasuredoubleTmax[3.12/38.35] Temperature maxMKphys.temperaturefloate1[50.0] Refererce energy {sigma}1, fixed to 50phys.energy;phys.atmol.levelfloatI1[5.8e-06/0.23] Photon Fluxcm**2.s.keV**-1phot.flux.densitydoublegamma[2.76/10.39] Spectral slope, {gamma}arith.gradfloatL[1.72/36.32] Length ScaleMmsrc.morph.scLengthfloatn10[0/136.12] Density maximumcm**-3phot.flux.densityfloatnb10[0/2582.54] Density preflarecm**-3phot.flux.densityfloatEco-en[0.1/194.3] Cutoff energy, el modelkeVem.energyfloatEco-wt[1.6/30.5] Cutoff energy, wt modelkeVem.energyfloatEco-tof[0/107.7] Cutoff energy, tof modelkeVem.energyfloatEco-co[10/30] Cutoff energy, co modelkeVem.energyfloatEnt-el[0/505.2834] Nonthermal energy, el model1e+24Jphys.energydoubleEnt-wt[0.0009/999] Nonthermal energy, wt model1e+24Jphys.energydoubleEnt-tof[0/999] Nonthermal energy, tof model1e+24Jphys.energydoubleEnt-co[0/3.6127] Nonthermal energy, co model1e+24Jphys.energyfloat