EVIDENCE OF SOLAR FLARE TRIGGERING DUE TO LOOP-LOOP INTERACTION CAUSED BY FOOTPOINT SHEAR MOTION

Journal Article · Wed Nov 10 04:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/723/2/1651· OSTI ID:21471226

Kumar, Pankaj; Srivastava, A K; Uddin, Wahab ^[1]; Somov, B V ^[2]; Manoharan, P K ^[3]; Erdelyi, R ^[4]

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1. Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital-263129 (India)
2. Astronomical Institute, Moscow State University, Universitetskij Prospekt 13, Moscow 119992 (Russian Federation)
3. Radio Astronomy Centre, NCRA, Tata Institute of Fundamental Research, Udhagamandalam (Ooty) 643 001 (India)
4. Solar Physics and Space Plasma Research Centre (SP2RC), Department of Applied Mathematics, University of Sheffield, Sheffield S3 7RH (United Kingdom)

We analyze multi-wavelength data of an M7.9/1N class solar flare which occurred on 2006 April 27 in AR NOAA 10875. GOES soft X-ray images provide the most likely signature of two interacting loops and their reconnection, which triggers the solar flare. TRACE 195 A images also reveal the loop-loop interaction and the formation of 'X' points with converging motion ({approx}30 km s{sup -1}) at the reconnection site in between this interacting loop system. This provides evidence of progressive reconnection and flare maximization at the interaction site in the active region. The absence of type III radio bursts during this time period indicates no opening of magnetic field lines during the flare energy release, which implies that the change of field line connectivity/orientation occurred only during the loop-loop interaction and reconnection process. The Ondrejov dynamic radio spectrum shows an intense decimetric (DCIM) radio burst (2.5-4.5 GHz, duration {approx}3 minutes) during the flare initiation, which reveals the signature of particle acceleration from the reconnection site during loop-loop interaction. The double-peak structures at 4.9 and 8.8 GHz provide the most likely confirmatory signature of the loop-loop interaction at the flare site in the active region. RHESSI hard X-ray images also show the loop-top and footpoint sources of the corresponding two-loop system, which act like current-carrying flux tubes with resultant opposite magnetic fields and net force of attraction, and their coalescence during the flare maximum. We also suggest that the shear motion/rotation of the footpoint of the smaller loop, which is anchored in the opposite polarity spot, may be responsible for the flare energy buildup and its eventual release due to the loop-loop interaction.

• OSTI ID: 21471226
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 723; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ATMOSPHERES
CHROMOSPHERE
COALESCENCE
ELECTROMAGNETIC RADIATION
FREQUENCY RANGE
GHZ RANGE
GHZ RANGE 01-100
HARD X RADIATION
IONIZING RADIATIONS
MAGNETIC FIELDS
MAIN SEQUENCE STARS
RADIATIONS
SOFT X RADIATION
SOLAR ACTIVITY
SOLAR ATMOSPHERE
SOLAR FLARES
STARS
STARSPOTS
STELLAR ACTIVITY
STELLAR ATMOSPHERES
STELLAR FLARES
SUN
SUNSPOTS
WAVELENGTHS
X RADIATION