Transverse Oscillations in Slender Ca II H Fibrils Observed with Sunrise/SuFI

S. Jafarzadeh, S. K. Solanki, R. Gafeira, M. Van Noort, P. Barthol, J. Blanco Rodríguez, J. C.Del Toro Iniesta, A. Gandorfer, L. Gizon, J. Hirzberger, M. Knölker, D. Orozco Suárez, T. L. Riethmüller, W. Schmidt

Research output: Contribution to journalArticle

Abstract

We present observations of transverse oscillations in slender Ca ii H fibrils (SCFs) in the lower solar chromosphere. We use a 1 hr long time series of high- (spatial and temporal-) resolution seeing-free observations in a 1.1 Å wide passband covering the line core of Ca ii H 3969 Å from the second flight of the Sunrise balloon-borne solar observatory. The entire field of view, spanning the polarity inversion line of an active region close to the solar disk center, is covered with bright, thin, and very dynamic fine structures. Our analysis reveals the prevalence of transverse waves in SCFs with median amplitudes and periods on the order of 2.4 ± 0.8 km s-1 and 83 ± 29 s, respectively (with standard deviations given as uncertainties). We find that the transverse waves often propagate along (parts of) the SCFs with median phase speeds of 9 ± 14 km s-1. While the propagation is only in one direction along the axis in some of the SCFs, propagating waves in both directions, as well as standing waves are also observed. The transverse oscillations are likely Alfvénic and are thought to be representative of magnetohydrodynamic kink waves. The wave propagation suggests that the rapid high-frequency transverse waves, often produced in the lower photosphere, can penetrate into the chromosphere with an estimated energy flux of ≈15 kW m-2. Characteristics of these waves differ from those reported for other fibrillar structures, which, however, were observed mainly in the upper solar chromosphere.

Original languageEnglish (US)
Article number9
JournalAstrophysical Journal, Supplement Series
Volume229
Issue number1
DOIs
StatePublished - Mar 2017

Keywords

  • Sun: chromosphere
  • Sun: magnetic fields
  • Sun: oscillations
  • techniques: imaging spectroscopy

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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    Jafarzadeh, S., Solanki, S. K., Gafeira, R., Noort, M. V., Barthol, P., Rodríguez, J. B., Iniesta, J. C. D. T., Gandorfer, A., Gizon, L., Hirzberger, J., Knölker, M., Suárez, D. O., Riethmüller, T. L., & Schmidt, W. (2017). Transverse Oscillations in Slender Ca II H Fibrils Observed with Sunrise/SuFI. Astrophysical Journal, Supplement Series, 229(1), [9]. https://doi.org/10.3847/1538-4365/229/1/9