Kuridze, D., Henriques, V., Mathioudakis, M. et al. (5 more authors) (2015) The dynamics of rapid redshifted and blueshifted excursions in the solar Hα line. The Astrophysical Journal, 802 (1). 26. ISSN 0004-637X
Abstract
We analyze high temporal and spatial resolution time-series of spectral scans of the Hα line obtained with the CRisp Imaging SpectroPolarimeter instrument mounted on the Swedish Solar Telescope. The data reveal highly dynamic, dark, short-lived structures known as Rapid Redshifted and Blueshifted Excursions (RREs, RBEs) that are on-disk absorption features observed in the red and blue wings of spectral lines formed in the chromosphere. We study the dynamics of RREs and RBEs by tracking their evolution in space and time, measuring the speed of the apparent motion, line of sight (LOS) Doppler velocity, and transverse velocity of individual structures. A statistical study of their measured properties shows that RREs and RBEs have similar occurrence rates, lifetimes, lengths, and widths. They also display non-periodic, nonlinear transverse motions perpendicular to their axes at speeds of 4–31 km s−1. Furthermore, both types of structures either appear as high speed jets and blobs that are directed outwardly from a magnetic bright point with speeds of 50–150 km s−1, or emerge within a few seconds. A study of the different velocity components suggests that the transverse motions along the LOS of the chromospheric flux tubes are responsible for the formation and appearance of these redshifted/blueshifted structures. The short lifetime and fast disappearance of the RREs/RBEs suggests that, similar to type II spicules, they are rapidly heated to transition region or even coronal temperatures. We speculate that the Kelvin–Helmholtz instability triggered by observed transverse motions of these structures may be a viable mechanism for their heating.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2015 The American Astronomical Society. Reproduced in accordance with the publisher's self-archiving policy. |
Keywords: | magnetohydrodynamics (MHD); Sun: atmosphere; Sun: chromosphere; Sun: magnetic fields; Sun: oscillations; waves |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Science (Sheffield) > School of Mathematics and Statistics (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 01 Nov 2016 15:08 |
Last Modified: | 01 Nov 2016 15:08 |
Published Version: | http://dx.doi.org/10.1088/0004-637X/802/1/26 |
Status: | Published |
Publisher: | American Astronomical Society |
Refereed: | Yes |
Identification Number: | 10.1088/0004-637X/802/1/26 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:106788 |