INTERFERENCE OF THE RUNNING WAVES AT LIGHT BRIDGES OF A SUNSPOT

Journal Article · Fri Jan 01 04:00:00 EST 2016 · Astrophysical Journal

DOI:https://doi.org/10.3847/0004-637X/816/1/30· OSTI ID:22521732

Su, J. T.; Priya, T. G.; Yu, S. J.; Zhang, M. ^[1]; Ji, K. F. ^[2]; Banerjee, D. ^[3]; Cao, W. D. ^[4]; Zhao, J. S.

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1. Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)
2. Kunming University of Science and Technology, Kunming 650093 (China)
3. Indian Institute of Astrophysics, Koramangala Bangalore 560034 (India)
4. Big Bear Solar Observatory, 40386 North Shore Lane, Big Bear City, CA 92314 (United States)

The observations of chromospheric oscillations of two umbral light bridges (LBs) within a sunspot from NOAA Active Region 12127 are presented. It was found that the running umbral waves with periods of 2.2–2.6 minutes underwent very fast damping before approaching umbral boundaries, while those with higher periods (>2.6 minutes) could propagate outside umbrae. On two sides of each LB adjacent to umbrae, the cross-wavelet spectra displayed that the oscillations on them had a common significant power region with dominant frequencies of 2–6 minutes and phase differences of ∼90°. A counterstream of two running umbral waves in the 2–6 minute frequency range propagated toward the LBs, where they encountered each other and gave rise to constructive or even destructive interference on the LBs. In addition, the velocity and density perturbations on the LBs were found in opposite phases suggesting that the perturbations were caused by the downward propagating waves.

• OSTI ID: 22521732
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 816; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CHROMOSPHERE
DAMPING
DENSITY
DISTURBANCES
EMISSION SPECTRA
INTERFERENCE
MAGNETIC FIELDS
OSCILLATIONS
SUN
SUNSPOTS
VELOCITY
VISIBLE RADIATION
WAVE PROPAGATION