First Imaging Observation of Standing Slow Wave in Coronal Fan Loops

Journal Article · Wed Sep 20 04:00:00 EDT 2017 · Astrophysical Journal Letters

DOI:https://doi.org/10.3847/2041-8213/AA880F· OSTI ID:22654388

Pant, V.; Tiwari, A.; Banerjee, D. ^[1]; Yuan, D. ^[2]

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1. Indian Institute of Astrophysics, Bangalore 560 034 (India)
2. Institute of Space Science and Applied Technology, Harbin Institute of Technology, Shenzhen 518000 (China)

We observe intensity oscillations along coronal fan loops associated with the active region AR 11428. The intensity oscillations were triggered by blast waves that were generated due to X-class flares in the distant active region AR 11429. To characterize the nature of oscillations, we created time–distance maps along the fan loops and noted that the intensity oscillations at two ends of the loops were out of phase. As we move along the fan loop, the amplitude of the oscillations first decreased and then increased. The out-of-phase nature together with the amplitude variation along the loop implies that these oscillations are very likely to be standing waves. The period of the oscillations is estimated to be ∼27 minutes, damping time to be ∼45 minutes, and phase velocity projected in the plane of sky to be ∼65–83 km s{sup −1}. The projected phase speeds were in the range of the acoustic speed of coronal plasma at about 0.6 MK, which further indicates that these are slow waves. To the best of our knowledge, this is the first report on the existence of the standing slow waves in non-flaring fan loops.

• OSTI ID: 22654388
• Journal Information: Astrophysical Journal Letters, Journal Name: Astrophysical Journal Letters Journal Issue: 1 Vol. 847; ISSN 2041-8205
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
AMPLITUDES
DAMPING
EXPLOSIONS
FLARING
OSCILLATIONS
PHASE VELOCITY
PLASMA
STANDING WAVES
SUN
ULTRAVIOLET RADIATION