NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Quantitative Examination of a Large Sample of Supra-Arcade Downflows in Eruptive Solar FlaresSunward-flowing voids above post-coronal mass ejection flare arcades were first discovered using the soft X-ray telescope aboard Yohkoh and have since been observed with TRACE (extreme ultraviolet (EUV)), SOHO/LASCO (white light), SOHO/SUMER (EUV spectra), and Hinode/XRT (soft X-rays). Supra-arcade downflow (SAD) observations suggest that they are the cross-sections of thin flux tubes retracting from a reconnection site high in the corona. Supra-arcade downflowing loops (SADLs) have also been observed under similar circumstances and are theorized to be SADs viewed from a perpendicular angle. Although previous studies have focused on dark flows because they are easier to detect and complementary spectral data analysis reveals their magnetic nature, the signal intensity of the flows actually ranges from dark to bright. This implies that newly reconnected coronal loops can contain a range of hot plasma density. Previous studies have presented detailed SAD observations for a small number of flares. In this paper, we present a substantial SADs and SADLs flare catalog. We have applied semiautomatic detection software to several of these events to detect and track individual downflows thereby providing statistically significant samples of parameters such as velocity, acceleration, area, magnetic flux, shrinkage energy, and reconnection rate. We discuss these measurements (particularly the unexpected result of the speeds being an order of magnitude slower than the assumed Alfven speed), how they were obtained, and potential impact on reconnection models.
Document ID
20110013463
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Savage, Sabrina L.
(Montana State Univ. Bozeman, MT, United States)
McKenzie, David E.
(Montana State Univ. Bozeman, MT, United States)
Date Acquired
August 25, 2013
Publication Date
March 9, 2011
Publication Information
Publication: The Astrophysical Journal
Publisher: Institute of Physics
Volume: 730
Issue: 2
Subject Category
Astrophysics
Report/Patent Number
GSFC.JA.4452.2011
Funding Number(s)
CONTRACT_GRANT: NNM07AB07C
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available