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Global Energetics of Solar Flares. V. Energy Closure in Flares and Coronal Mass Ejections

Aschwanden, Markus J. and Caspi, Amir and Cohen, Christina M. S. and Holman, Gordon and Jing, Ju and Kretzschmar, Matthieu and Kontar, Eduard P. and McTiernan, James M. and Mewaldt, Richard A. and O’Flannagain, Aidan and Richardson, Ian G. and Ryan, Daniel and Warren, Harry P. and Xu, Yan (2017) Global Energetics of Solar Flares. V. Energy Closure in Flares and Coronal Mass Ejections. Astrophysical Journal, 836 (1). Art. No. 17. ISSN 0004-637X.

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In this study we synthesize the results of four previous studies on the global energetics of solar flares and associated coronal mass ejections (CMEs), which include magnetic, thermal, nonthermal, and CME energies in 399 solar M- and X-class flare events observed during the first 3.5 yr of the Solar Dynamics Observatory (SDO) mission. Our findings are as follows. (1) The sum of the mean nonthermal energy of flare-accelerated particles (E_(nt)), the energy of direct heating (E_(dir)), and the energy in CMEs (E_(CME)), which are the primary energy dissipation processes in a flare, is found to have a ratio of E_(nt) + E_(dir) + E_(CME)/E_(mag) = 0.87 ± 0.18, compared with the dissipated magnetic free energy E_(mag), which confirms energy closure within the measurement uncertainties and corroborates the magnetic origin of flares and CMEs. (2) The energy partition of the dissipated magnetic free energy is: 0.51 ± 0.17 in nonthermal energy of ⩾ 6 keV electrons, 0.17 ± 0.17 in nonthermal ⩾ 1 MeV ions, 0.07 ± 0.14 in CMEs, and 0.07 ± 0.17 in direct heating. (3) The thermal energy is almost always less than the nonthermal energy, which is consistent with the thick-target model. (4) The bolometric luminosity in white-light flares is comparable to the thermal energy in soft X-rays (SXR). (5) Solar energetic particle events carry a fraction ≈ 0.03 of the CME energy, which is consistent with CME-driven shock acceleration. (6) The warm-target model predicts a lower limit of the low-energy cutoff at e_c ≈ 6 keV, based on the mean peak temperature of the differential emission measure of T_e = 8.6 MK during flares. This work represents the first statistical study that establishes energy closure in solar flare/CME events.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Caspi, Amir0000-0001-8702-8273
Cohen, Christina M. S.0000-0002-0978-8127
Mewaldt, Richard A.0000-0003-2178-9111
Richardson, Ian G.0000-0002-3855-3634
Xu, Yan0000-0003-2808-7964
Additional Information:© 2017 The American Astronomical Society. Received 2016 October 26; revised 2017 January 2; accepted 2017 January 3; published 2017 February 6. We acknowledge useful comments from an anonymous referee and discussions with Gordon Emslie, Nat Gopalswamy, Ryan Milligan, Nariaki Nitta, Albert Shih, Manuela Temmer, Barbara Thompson, Astrid Veronig, Angelos Vourlidas, Alexander Warmuth, and Jie Zhang. Contributors to the analysis of SEP events are Richard Mewaldt, Christina Cohen, David Lario, Glenn Mason, Ian Richardson, and Mihir Desai. This work was partially supported by NASA contract NNX16AF92G of the project Global Energetics of Solar Flares and CMEs, and by NASA contract NNG04EA00C of the SDO/AIA instrument. Amir Caspi and Jim McTiernan were supported by NASA Grants NNX15AK26G and NNX14AH54G, and by NASA Contract NAS5-90833. Christina Cohen and Richard Mewaldt were supported by NASA under grants NNX13A66G and subcontract 00008864NNX15AG09G of grant NNX15AG09G. Daniel Ryan was supported by the NASA PostDoc program through the Universities Space Research Association (USRA) and the Royal Observatory of Belgium (ROB).
Group:Space Radiation Laboratory
Funding AgencyGrant Number
NASA Postdoctoral ProgramUNSPECIFIED
Royal Observatory of BelgiumUNSPECIFIED
Issue or Number:1
Record Number:CaltechAUTHORS:20170206-101429091
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Official Citation:Markus J. Aschwanden et al 2017 ApJ 836 17
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:74071
Deposited By: Tony Diaz
Deposited On:06 Feb 2017 20:14
Last Modified:09 Mar 2020 13:19

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