Refinements to flare energy estimates: A followup to "Energy partition in two solar flare/CME events" by A. G. Emslie et al

• Published in: Journal of Geophysical Research: Space Physics 2005-11, Vol.110 (A11), p.A11103.1-n/a
• Main Authors: Emslie, A. G., Dennis, B. R., Holman, G. D., Hudson, H. S.
• Format: Article
• Language: English
• Subjects: coronal mass ejections; Earth sciences; Earth, ocean, space; energetics; Exact sciences and technology; optical emission; solar energetic particles; solar flares; X rays
• ISSN: 0148-0227; 2156-2202
• DOI: 10.1029/2005JA011305

Emslie et al. (2004) reported estimates of the energy in the different flare and coronal mass ejection (CME) components of two major solar events with unprecedented observational coverage, one on 21 April 2002 and the other on 23 July 2002. On the basis of these estimates, it appeared that the summed energy content of the different flare components was significantly lower than the total energy of the CME, leading them to reach the “cautious” conclusion that “in both events the coronal mass ejection has the dominant component of the released energy,” amounting to approximately 30% of the available magnetic energy. In this note we present revised estimates of the flare thermal energies in the two events and also add a consideration of the total radiant energy of the events obtained by scaling the measured soft X‐ray luminosity based on Solar Radiation and Climate Experiment (SORCE) total solar irradiance measurements for the 28 October 2003 event. Recognizing that many of these energetic components are interrelated, we also take care to distinguish between “primary” components of energy (e.g., the magnetic field), “intermediate” components (e.g., accelerated particles and thermal plasma), and “final” components (e.g., kinetic energy of ejecta, radiant energy in various wave bands). We note that since the values of these components are not all independent, careful tallying is necessary to arrive at an overall energy budget for the event. The best estimates for the energies of the various components still show that the CME contains the greatest fraction of the released energy in both events. However, given the large uncertainties in the energies of the different flare components and the higher estimates of radiant energy obtained by scaling from the SORCE measurements, the results are also consistent with the flare and CME energies in both events being comparable, with a common value of ∼1032 ergs.