Early evolution of an energetic coronal mass ejection and its relation to EUV waves

Journal Article · Wed Dec 10 04:00:00 EST 2014 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/797/1/37· OSTI ID:22370041

Liu, Rui; Wang, Yuming; Shen, Chenglong ^[1]

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1. CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei 230026 (China)

We study a coronal mass ejection (CME) associated with an X-class flare whose initiation is clearly observed in the low corona with high-cadence, high-resolution EUV images, providing us a rare opportunity to witness the early evolution of an energetic CME in detail. The eruption starts with a slow expansion of cool overlying loops (∼1 MK) following a jet-like event in the periphery of the active region. Underneath the expanding loop system, a reverse S-shaped dimming is seen immediately above the brightening active region in hot EUV passbands. The dimming is associated with a rising diffuse arch (∼6 MK), which we interpret as a preexistent, high-lying flux rope. This is followed by the arising of a double hot channel (∼10 MK) from the core of the active region. The higher structures rise earlier and faster than lower ones, with the leading front undergoing extremely rapid acceleration up to 35 km s{sup –2}. This suggests that the torus instability is the major eruption mechanism and that it is the high-lying flux rope rather than the hot channels that drives the eruption. The compression of coronal plasmas skirting and overlying the expanding loop system, whose aspect ratio h/r increases with time as a result of the rapid upward acceleration, plays a significant role in driving an outward-propagating global EUV wave and a sunward-propagating local EUV wave, respectively.

• OSTI ID: 22370041
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 797; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCELERATION
ASPECT RATIO
COMPRESSION
ERUPTION
EVOLUTION
EXPANSION
EXTREME ULTRAVIOLET RADIATION
HOT CHANNEL
INSTABILITY
MASS
PLASMA
RESOLUTION
SOLAR CORONA
SUN