The X10 flare on 29 October 2003: Was it triggered by magnetic reconnection between counter-helical fluxes?

Document Type

Article

Publication Date

2-1-2007

Abstract

Vector magnetograms taken at Huairou Solar Observing Station (HSOS) and Mees Solar Observatory (MSO) reveal that the super active region (AR) NOAA 10486 was a complex region containing current helicity flux of opposite signs. The main positive sunspots were dominated by negative helicity fields, while positive helicity patches persisted both inside and around the main positive sunspots. Based on a comparison of two days of deduced current helicity density, pronounced changes associated with the occurrence of an X10 flare that peaked at 20:49 UT on 29 October 2003 were noticed. The average current helicity density (negative) of the main sunspots decreased significantly by about 50%. Accordingly, the helicity densities of counter-helical patches (positive) were also found to decay by the same proportion or more. In addition, two hard X-ray (HXR) "footpoints" were observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) during the flare in the 50∈-∈100 keV energy range. The cores of these two HXR footpoints were adjacent to the positions of two patches with positive current helicity that disappeared after the flare. This strongly suggested that the X10 flare on 29 October 2003 resulted from reconnection between magnetic flux tubes having opposite current helicity. Finally, the global decrease of current helicity in AR 10486 by ∼ 50% can be understood as the helicity launched away by the halo coronal mass ejection (CME) associated with the X10 flare. © Springer 2007.

Identifier

34047114820 (Scopus)

Publication Title

Solar Physics

External Full Text Location

https://doi.org/10.1007/s11207-006-0316-x

e-ISSN

1573093X

ISSN

00380938

First Page

253

Last Page

262

Issue

2

Volume

240

Grant

ATM 05-48952

Fund Ref

National Science Foundation

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