Observational Evidence for Mode Coupling in the Chromospheric Network
Open Access
- 20 April 2003
- journal article
- research article
- Published by American Astronomical Society in The Astrophysical Journal
- Vol. 587 (2), 806-817
- https://doi.org/10.1086/368304
Abstract
Oscillations in network bright points (NBPs) are studied at a variety of chromospheric heights. In particular, the three-dimensional variation of NBP oscillations is studied using image segmentation and cross-correlation analysis between images taken in light of Ca II K3, Hα core, Mg I b2, and Mg I b1 - 0.4 Å. Wavelet analysis is used to isolate wave packets in time and to search for height-dependent time delays that result from upward- or downward-directed traveling waves. In each NBP studied, we find evidence for kink-mode waves (1.3, 1.9 mHz), traveling up through the chromosphere and coupling with sausage-mode waves (2.6, 3.8 mHz). This provides a means for depositing energy in the upper chromosphere. We also find evidence for other upward- and downward-propagating waves in the 1.3-4.6 mHz range. Some oscillations do not correspond to traveling waves, and we attribute these to waves generated in neighboring regions.Keywords
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