EVIDENCE FOR MIXED HELICITY IN ERUPTING FILAMENTS

Journal Article · Sun Sep 20 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/703/1/976· OSTI ID:21371945

Muglach, K ^[1]; Wang, Y -M ^[2]; Kliem, B ^[3]

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1. ARTEP, Inc., Ellicott City, MD (United States)
2. Space Science Division, Naval Research Laboratory, Washington, DC 20375-5352 (United States)
3. MSSL, University College London, Holmbury St. Mary, Dorking, Surrey (United Kingdom)

Erupting filaments are sometimes observed to undergo a rotation about the vertical direction as they rise. This rotation of the filament axis is generally interpreted as a conversion of twist into writhe in a kink-unstable magnetic flux rope. Consistent with this interpretation, the rotation is usually found to be clockwise (as viewed from above) if the post-eruption arcade has right-handed helicity, but counterclockwise if it has left-handed helicity. Here, we describe two non-active-region filament events recorded with the Extreme-Ultraviolet Imaging Telescope on the Solar and Heliospheric Observatory in which the sense of rotation appears to be opposite to that expected from the helicity of the post-event arcade. Based on these observations, we suggest that the rotation of the filament axis is, in general, determined by the net helicity of the erupting system, and that the axially aligned core of the filament can have the opposite helicity sign to the surrounding field. In most cases, the surrounding field provides the main contribution to the net helicity. In the events reported here, however, the helicity associated with the filament 'barbs' is opposite in sign to and dominates that of the overlying arcade.

• OSTI ID: 21371945
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 703; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ATMOSPHERES
ELECTROMAGNETIC RADIATION
ERUPTION
EXTREME ULTRAVIOLET RADIATION
HELICITY
MAGNETIC FIELDS
MAGNETIC FLUX
MAIN SEQUENCE STARS
PARTICLE PROPERTIES
RADIATIONS
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOLAR CORONA
SOLAR FLARES
STARS
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR CORONAE
STELLAR FLARES
SUN
TELESCOPES
ULTRAVIOLET RADIATION