OBSERVATION OF A QUASIPERIODIC PULSATION IN HARD X-RAY, RADIO, AND EXTREME-ULTRAVIOLET WAVELENGTHS

Journal Article · Sun May 01 00:00:00 EDT 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/822/1/7· OSTI ID:22662984

Kumar, Pankaj; Cho, Kyung-Suk ^[1]

---

1. Korea Astronomy and Space Science Institute (KASI), Daejeon, 305-348 (Korea, Republic of)

We present a multiwavelength analysis of a quasiperiodic pulsation (QPP) observed in the hard X-ray (HXR), radio, and extreme-ultraviolet (EUV) channels during an M1.9 flare that occurred on 2011 September 23–24. The nonthermal HXR emission in 25–50 keV observed by RHESSI shows five distinct impulsive peaks of decaying amplitude with a period of about 3 minutes. A similar QPP was observed in the microwave emission recorded by the Nobeyama Radioheliograph and Polarimeter in the 2, 3.75, 9.4, and 17 GHz channels. Interestingly, the 3-minute QPP was also observed in the metric and decimetric radio frequencies (25–180, 245, 610 MHz) as repetitive type III bursts. Multiwavelength observations from the Solar Dynamics Observatory /Atmospheric Image Assembly, Hinode /SOT, and Solar TErrestrial RElations Observatory /SECCHI suggest a fan-spine topology at the eruption site, associated with the formation of a quasi-circular ribbon during the flare. A small filament was observed below the fan loops before the flare onset. The filament rose slowly and interacted with the ambient field. This behavior was followed by an untwisting motion of the filament. Two different structures of the filament showed an approximately 3-minute periodic alternate rotation in the clockwise and counterclockwise directions. The 3-minute QPP was found to highly correlate with 3-minute oscillations in a nearby sunspot. We suggest that the periodic reconnection (modulated either by a sunspot slow-mode wave or by an untwisting filament) at a magnetic null point most likely causes the repetitive particle acceleration, generating the QPP observed in HXR, microwave, and type III radio bursts.

• OSTI ID: 22662984
• Journal Information: Astrophysical Journal, Vol. 822, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCELERATION
APPROXIMATIONS
BLOWERS
COSMIC RADIO SOURCES
DECAY
DECAY AMPLITUDES
EMISSION
EXTREME ULTRAVIOLET RADIATION
HARD X RADIATION
MAGNETIC FIELDS
MICROWAVE RADIATION
OSCILLATIONS
PERIODICITY
POLARIMETERS
PULSATIONS
RADIOWAVE RADIATION
ROTATION
SUN
SUNSPOTS
WAVELENGTHS