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Phase mixing of standing continuum Alfv\'en waves and/or continuum slow waves in atmospheric magnetic structures such as coronal arcades can create the apparent effect of a wave propagating across the magnetic field. We observe a prominence…

Solar and Stellar Astrophysics · Physics 2017-06-28 J. O. Raes , T. Van Doorsselaere , M. Baes , A. N. Wright

Quasi-periodic propagating disturbances in coronal structures have been interpreted as slow magneto-acoustic waves and/or periodic upflows. Here we aim to understand their nature from the observed properties using a three-hour imaging…

Solar and Stellar Astrophysics · Physics 2015-06-11 S. Krishna Prasad , D. Banerjee , T. Van Doorsselaere , J. Singh

The observed splittings of solar oscillation frequencies can be employed to separate the effects of internal solar rotation and to estimate the contribution from a large-scale magnetic field or any latitude-dependent thermal perturbation…

Astrophysics · Physics 2007-05-23 H. M. Antia , S. M. Chitre , M. J. Thompson

Context: Solar pores are small sunspots lacking a penumbra that have a prevailing vertical magnetic field component. They can include light bridges at places with locally reduced magnetic field. Like sunspots, they exhibit a wide range of…

Solar and Stellar Astrophysics · Physics 2015-06-17 M. Sobotka , M. Švanda , J. Jurčák , P. Heinzel , D. Del Moro , F. Berrilli

We study properties of waves of frequencies above the photospheric acoustic cut-off of $\approx$5.3 mHz, around four active regions, through spatial maps of their power estimated using data from Helioseismic and Magnetic Imager (HMI) and…

Solar and Stellar Astrophysics · Physics 2015-06-05 S. P. Rajaguru , S. Couvidat , Xudong Sun , K. Hayashi , H. Schunker

In this work, we studied oscillation parameters in faculae above magnetic knots and in the adjacent to them areas. Using SDO data we analysed oscillations in magnetic strength, Doppler velocity, and intensity signals for the lower…

Solar and Stellar Astrophysics · Physics 2016-08-17 Andrei A. Chelpanov , Nikolai I. Kobanov , Dmitry Y. Kolobov

Waves are thought to play a significant role in the heating of the solar atmosphere and the acceleration of the wind. Among the many types of waves observed in the Sun, the so-called p-modes with a 3 mHz frequency peak dominate the lower…

The subject of this study is oscillations in the lower atmosphere in coronal-hole regions, where the conditions are favorable for propagation between the atmospheric layers. Based on spectroscopic observations in photospheric and…

Solar and Stellar Astrophysics · Physics 2021-12-22 Andrei Chelpanov , Nikolai Kobanov , Maksim Chelpanov , Aleksandr Kiselev

Sunspots are prominent manifestations of solar magnetoconvection and imaging their subsurface structure is an outstanding problem of wide physical importance. Travel times of seismic waves that propagate through these structures are…

Solar and Stellar Astrophysics · Physics 2015-06-05 Shravan Hanasoge , Aaron Birch , Laurent Gizon , Jeroen Tromp

The solar atmosphere is known to be replete with magneto-hydrodynamic wave modes, and there has been significant investment in understanding how these waves propagate through the Sun's atmopshere and deposit their energy into the plasma.…

Solar and Stellar Astrophysics · Physics 2023-02-14 R. J. Morton , R. Sharma , E. Tajfirouze , H. Miriyala

We studied the physical parameters of the penumbra in a large and fully-developed sunspot, one of the largest over the last two solar cycles, by using full-Stokes measurements taken at the photospheric Fe I 617.3 nm and chromospheric Ca II…

Solar and Stellar Astrophysics · Physics 2019-03-20 Mariarita Murabito , I. Ermolli , F. Giorgi , M. Stangalini , S. L. Guglielmino , S. Jafarzadeh , H. Socas-Navarro , P. Romano , F. Zuccarello

Observations of the upper chromosphere shows an enormous amount of intricate fine structure. Much of this comes in the form of linear features which are most often assumed to be well aligned with the direction of the magnetic field in the…

Solar and Stellar Astrophysics · Physics 2017-10-23 Juan Martínez-Sykora , Bart De Pontieu , Mats Carlsson , Viggo Hansteen

The detection of upward propagating internal gravity waves at the base of the Sun's chromosphere has recently been reported by Straus et al., who postulated that these may efficiently couple to Alfven waves in magnetic regions. This may be…

Solar and Stellar Astrophysics · Physics 2015-05-14 Marie Newington , Paul Cally

Acoustic wave heating is believed to contribute significantly to the missing energy input required to maintain the solar chromosphere in its observed state. We studied the propagation of waves above the acoustic cutoff in the upper…

Solar and Stellar Astrophysics · Physics 2023-03-29 Momchil E. Molnar , Kevin P. Reardon , Steven R. Cranmer , Adam F. Kowalski , Ivan Milic

We found that oscillations of LOS velocity in H-alpha are different for various parts of faculae regions. Power spectra show that the contribution of low-frequency modes (1.2 - 2 mHz) increase at the network boundaries. Three and five-…

Solar and Stellar Astrophysics · Physics 2011-10-10 N. I. Kobanov , V. A. Pulyaev

The solar wind is a magnetized plasma and as such exhibits collective plasma behavior associated with its characteristic spatial and temporal scales. The characteristic length scales include the size of the heliosphere, the collisional mean…

Space Physics · Physics 2020-01-01 Daniel Verscharen , Kristopher G. Klein , Bennett A. Maruca

The turbulent spectrum of magnetic fluctuations in the solar wind displays a spectral break at ion characteristic scales. At electron scales the spectral shape is not yet completely established. Here, we perform a statistical study of 102…

Plasma Physics · Physics 2011-11-28 O. Alexandrova , C. Lacombe , A. Mangeney , R. Grappin

We analyze a 1-hour time series of Ca II H intensity spectra and polarimetric spectra around 630 nm to derive the signature of the chromospheric heating and to investigate its relation to magnetic fields. We derived several characteristic…

Astrophysics · Physics 2008-02-08 C. Beck , W. Schmidt , R. Rezaei , W. Rammacher

At the surface of the Sun, acoustic waves appear to be affected by the presence of strong magnetic fields in active regions. We explore the possibility that the inclined magnetic field in sunspot penumbrae may convert primarily vertically…

Astrophysics · Physics 2009-11-13 H. Schunker , D. C. Braun , C. Lindsey , P. S. Cally

We solve the problem of propagation and dissipation of Alfvenic turbulence in a model solar atmosphere consisting of a static photosphere and chromosphere, transition region, and open corona and solar wind, using a phenomenological model…

Astrophysics · Physics 2011-02-11 A. Verdini , M. Velli