Multi-thermal dynamics and energetics of a coronal mass ejection in the low solar atmosphere⋆
SUPA School of Physics & Astronomy, University of Glasgow, Glasgow, G12 8QQ, UK
Received: 31 May 2012
Accepted: 30 January 2013
Aims. The aim of this work is to determine the multi-thermal characteristics and plasma energetics of an eruptive plasmoid and occulted flare observed by the Solar Dynamics Observatory’s Atmospheric Imaging Assembly (SDO/AIA).
Methods. We study a 2010 Nov. 3 event (peaking at 12:20 UT in GOES soft X-rays) of a coronal mass ejection and occulted flare that demonstrates the morphology of a classic erupting flux rope. The high spatial and time resolution and six coronal channels of the SDO/AIA images allows the dynamics of the multi-thermal emission during the initial phases of eruption to be studied in detail. The differential emission measure is calculated, using an optimized version of a regularized inversion method, for each pixel across the six channels at different times, resulting in emission measure maps and movies in a variety of temperature ranges.
Results. We find that the core of the erupting plasmoid is hot (8–11, 11–14 MK) with a similarly hot filamentary “stem” structure connecting it to the lower atmosphere, which could be interpreted as the current sheet in the flux rope model, though is wider than these models suggest. The velocity of the leading edge of the eruption is 597–664 km s-1 in the temperature range ≥3–4 MK and between 1029–1246 km s-1 for ≤2–3 MK. We estimate the density (in 11–14 MK) of the erupting core and stem during the impulsive phase to be about 3 × 109 cm-3, 6 × 109 cm-3, 9 × 108 cm-3 in the plasmoid core, stem, and surrounding envelope of material. This gives thermal energy estimates of 5 × 1029 erg, 1 × 1029 erg, and 2 × 1030 erg. The kinetic energy for the core and envelope is slightly lower. The thermal energy of the core and current sheet grows during the eruption, suggesting continuous influx of energy presumably via reconnection.
Conclusions. The combination of the optimized regularized inversion method and SDO/AIA data allows the multi-thermal characteristics (i.e. velocity, density, and thermal energies) of the plasmoid eruption to be determined.
Key words: Sun: X-rays, gamma rays / Sun: UV radiation / Sun: activity / Sun: flares / Sun: corona / techniques: image processing
A movie is available in electronic form at http://www.aanda.org
© ESO, 2013