The coronal mass ejection associated with the loop eruption and coronal dimmings on 2009 December 13

Abstract

By using the multi-wavelength observations from the Solar Terrestrial Relations Observatory (STEREO), the Solar and Heliospheric Observatory (SOHO), the Transition Region and Coronal Explorer (TRACE) and the HIN-ODE, we study a coronal mass ejection (CME) and associated coronal dimming occurred on 2009 December 13, as a consequence of the expansion and eruption of EUV loops. The activities were probably triggered by the new flux emergence and the convergence motions, which were evident in the magnetograms from Michelson Doppler Imager (MDI) on the SOHO. The emergence led to the destabilization and eruption of the preexistent flux rope, which was highly-sheared over the polarity inversion line. Driven by the ejection of the flux rope, the overlying loops initially slowly rose and then erupted. As a result, two coronal dimming regions formed at the footprints of the loops and a B1.9 flare, about half an hour later, occurred in the eruptive region near one foot of the eruptive loops. The CME had a very close temporal and spatial relationship to the expanding loops, and it is very likely that the CME directly developed from the eruptive loops. The CME mass calculated from the EUV dimming was of the same order of the typical CME mass, suggesting that the dimming region supplied major of the mass for the CME. The kinematic evolution of the CME was basically consistent with the three-phases scenario: the initiation phase, impulsive acceleration phase, and propagation phase. The onset of the CME could be well explained by the emerging flux trigger mechanism.

The magnetic field in the solar atmosphere

“…The majority of ejecta, including CMEs associated with disappearing filaments (Yurchyshyn et al 2001;Cho et al 2013) or eruptive X-ray loops (Mandrini et al 2005;Zheng et al 2011), propagate away from the Sun in the form of magnetic clouds (MCs) and hence actively carry helicity away. MCs are force-free regions of enhanced magnetic field strength, with the field vector monotonically rotating as they journey with the solar wind.…”

The Magnetic Field in the Solar Atmosphere

“…The majority of ejecta, including CMEs associated with disappearing filaments or eruptive X-ray loops (Mandrini et al, 2005;Zheng et al, 2011), propagate away from the Sun in the form of magnetic clouds (MCs) and hence actively carry helicity away. MCs are force-free regions of enhanced magnetic field strength, with the field vector monotonically rotating as they journey with the solar wind.…”

Solar Stereoscopy and Tomography

“…Sequential (homologous) CME events may cause "double dimmings" (Li et al, 2010b). EUV dimming may occur at two footpoint locations of an eruptive loop, especially in cases with emerging flux trigger mechanisms (Zheng et al, 2011). The detection and measurement of coronal EUV dimming regions can now be conducted with automated algorithms (Attrill and Wills-Davey, 2010).…”