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We analyze spectropolarimetric observations of the chromospheric Ca II 8542 line taken by the Interferometric Bidimensional Spectrometer (IBIS) at the Dunn Solar Telescope and photospheric Fe I 6302 lines obtained with the Solar Optical…

Solar and Stellar Astrophysics · Physics 2017-12-20 Ali G. A. Abdelkawy , Abdelrazek M. K. Shaltout , M. M. Beheary

We analyze spectropolarimetric observations of the chromospheric Ca II 8542 A line taken by the Interferometric Bidimensional Spectrometer (IBIS) at the Dunn Solar Telescope. The data were observed on 2012 January 29 for the NOAA active…

Solar and Stellar Astrophysics · Physics 2017-12-20 Ali G. A. Abdelkawy , Abdelrazek M. K. Shaltout , M. M. Beheary , T. A. Schad

Stepwise changes of the photospheric magnetic field, which often becomes more horizontal, have been observed during many flares. Previous interpretations include coronal loops that contract and it has been speculated that such jerks could…

Solar and Stellar Astrophysics · Physics 2017-01-04 Lucia Kleint

We propose a method to derive the line-of-sight magnetic flux density from measurements in the chromospheric Ca II IR line at 854.2 nm. The method combines two well-understood techniques, the center-of-gravity and bisector methods, in a…

Solar and Stellar Astrophysics · Physics 2009-12-18 F. Wöger , S. Wedemeyer-Böhm , H. Uitenbroek , T. Rimmele

We present a statistical analysis of network and internetwork properties in the photosphere and the chromosphere. For the first time we simultaneously observed (a) the four Stokes parameters of the photospheric iron line pair at 630.2 nm…

Astrophysics · Physics 2007-05-23 R. Rezaei , R. Schlichenmaier , C. Beck , W. Schmidt

We study the properties of waves in a facular region of moderate strength in the photosphere and chromosphere. Our aim is to analyse statistically the wave periods, power and phase relations as a function of the magnetic field strength and…

Solar and Stellar Astrophysics · Physics 2015-06-17 Roman Kostik , Elena Khomenko

Aims. We analyze observational data from 4 instruments to study the correlations between chromospheric emission, spanning the heights from the temperature minimum region to the middle chromosphere, and photospheric magnetic field. Methods:…

Solar and Stellar Astrophysics · Physics 2014-11-20 Maria A. Loukitcheva , Sami K. Solanki , Stephen M. White

We investigated the diagnostic potential of the Stokes $V$ profile of the H$\alpha$ line to probe the chromospheric line-of-sight (LOS) magnetic field ($B_{\mathrm{LOS}}$) by comparing the $B_{\mathrm{LOS}}$ inferred from the weak field…

Solar and Stellar Astrophysics · Physics 2023-04-05 Harsh Mathur , K. Nagaraju , Jayant Joshi , Jaime de la Cruz Rodríguez

The solar chromosphere is a vigorously dynamic region of the sun, where waves and magnetic fields play an important role. To improve chromospheric diagnostics, we present new observations in Ca II 8542 carried out with the SST/CRISP on La…

Solar and Stellar Astrophysics · Physics 2015-03-14 Jaime de la Cruz Rodríguez , Hector Socas-Navarro , Michiel van Noort , Luc Rouppe van der Voort

Active regions often host large-scale gas flows in the chromosphere presumably directed along curved magnetic field lines. Spectropolarimetric observations of these flows are critical to understanding the nature and evolution of their…

Solar and Stellar Astrophysics · Physics 2011-01-05 Tom Schad , Sarah Jaeggli , Haosheng Lin , Matthew Penn

The nonlinear force-free field (NLFFF) modeling has been extensively used to infer the three-dimensional (3D) magnetic field in the solar corona. One of the assumptions in the NLFFF extrapolation is that the plasma beta is low, but this…

Solar and Stellar Astrophysics · Physics 2020-07-30 Yusuke Kawabata , Andrés Asensio Ramos , Satoshi Inoue , Toshifumi Shimizu

We explore the photospheric and chromospheric magnetic field in an emerging flux region. An image of the equivalent width of the He I 10830 A red blended component shows the presence of filamentary structures that might be interpreted as…

Solar and Stellar Astrophysics · Physics 2010-01-14 A. Asensio Ramos , J. Trujillo Bueno

We use joint observations obtained with the Hinode space observatory and the Interferometric Bidimensional Spectrometer (IBIS) installed at the DST of the NSO/SP to investigate the morphology and dynamics of (a) non-magnetic and (b)…

Solar and Stellar Astrophysics · Physics 2009-12-18 F. Wöger , S. Wedemeyer-Böhm , T. Rimmele

Context. A proper estimate of the chromospheric magnetic fields is believed to improve modelling of both active region and coronal mass ejection evolution. Aims. We investigate the similarity between the chromospheric magnetic field…

We explore the diagnostic potential of the H$\alpha$ line for probing the chromospheric magnetic field using a realistic 3D radiative magnetohydrodynamic (rMHD) model. The Stokes profiles of the H$\alpha$ line are synthesized through full…

Solar and Stellar Astrophysics · Physics 2025-07-08 Harsh Mathur , Jayant Joshi , Thore Espedal Moe , Tiago M. D. Pereira , K. Nagaraju

The Solar Mean Magnetic Field (SMMF) is the mean value of the line of sight (LOS) component of the solar vector magnetic field averaged over the visible hemisphere of the Sun. So far, the studies on SMMF have mostly been confined to the…

Solar and Stellar Astrophysics · Physics 2023-06-28 M. Vishnu , K. Nagaraju , Harsh Mathur

Besides their own intrinsic interest, correct interpretation of solar surface magnetic field observations is crucial to our ability to describe the global magnetic structure of the solar atmosphere. Photospheric magnetograms are often used…

Solar and Stellar Astrophysics · Physics 2010-10-29 Gordon J. D. Petrie , Irina Patrikeeva

Sequences of line-of-sight (LOS) magnetograms recorded by the Michelson-Doppler Imager are used to quantitatively characterize photospheric magnetic structure and evolution in three active regions that rotated across the Sun's disk during…

Solar and Stellar Astrophysics · Physics 2015-05-27 B. T. Welsch , S. Christe , J. M. McTiernan

The fine-structure of magnetic field of a sunspot penumbra in the upper chromosphere is to be explored and compared to that in the photosphere. High spatial resolution spectropolarimetric observations were recorded with the 1.5-meter GREGOR…

We present properties of intensity oscillations of a sunspot in the photosphere and chromosphere using G~band and CaIIH filtergrams from Hinode. Intensity power maps as function of magnetic field strength and frequency reveal reduction of…

Solar and Stellar Astrophysics · Physics 2015-02-17 Ankala Raja Bayanna , Shibu K Mathew , Brajesh Kumar , Rohan E Louis , Parameswaran Venkatakrishnan
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