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Related papers: Optimal spectral lines for measuring chromospheric…

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Important insights into the formation, structure, evolution and environment of all types of stars can be obtained through the measurement of their winds and possible magnetospheres. However, this has hardly been done up to now mainly…

Spectropolarimetric results of Fraunhofer lines between 516.3nm and 532.6nm are presented in local upper solar chromosphere, transition zone and inner corona below a height of about 0.04 solar radius above the solar limb. The data were…

Solar and Stellar Astrophysics · Physics 2024-03-26 Z. Q. Qu , L. Chang , G. T. Dun , X. M. Cheng , C. Fang , Z. Xu , D. Yuan , L. H. Deng , X. Y. Zhang

The Mg II h and k lines are among the strongest in the near-ultraviolet solar spectrum and their line core originates in the upper chromosphere, just below the transition region. Consequently, they have become one of the main targets for…

Solar and Stellar Astrophysics · Physics 2023-01-18 David Afonso Delgado , Tanausú del Pino Alemán , Javier Trujillo Bueno

Adopting the thermal free-free emission mechanism, the coronal and chromospheric magnetic fields are derived from the polarization and spectral observations with the Nobeyama Radioheliograph at 1.76 cm. The solar active regions (AR) located…

Solar and Stellar Astrophysics · Physics 2018-02-14 A. Mouner , Abdelrazek M. K. Shaltout , M. M. Beheary , K. A. K. Gadallah , K. A. Edris

The Fe I 6173 {\AA} line is widely used in the measurements of vector magnetic fields by instruments including the Helioseismic and Magnetic Imager (HMI). We perform non-local thermodynamic equilibrium calculations of this line based on…

Solar and Stellar Astrophysics · Physics 2018-04-10 Jie Hong , M. D. Ding , Ying Li , Mats Carlsson

The new CRISP filter at the Swedish 1-m Solar Telescope provides opportunities for observing the solar atmosphere with unprecedented spatial resolution and cadence. In order to benefit from the high quality of observational data from this…

Solar and Stellar Astrophysics · Physics 2012-04-23 Jaime de la Cruz Rodríguez

Understanding structures and evolutions of the magnetic fields and plasma in multiple layers on the Sun is very important. A force-free magnetic field which is an accurate approximation of the solar corona due to the low plasma $\beta$ has…

Solar and Stellar Astrophysics · Physics 2022-03-30 Xiaoshuai Zhu , Thomas Neukirch , Thomas Wiegelmann

2008 marks the 100th anniversary of the discovery of astrophysical magnetic fields, when George Ellery Hale recorded the Zeeman splitting of spectral lines in sunspots. With the introduction of Babcock's photoelectric magnetograph it soon…

Solar and Stellar Astrophysics · Physics 2015-05-13 J. O. Stenflo

We use images of high spatial and temporal resolution, obtained using both ground- and space-based instrumentation, to investigate the role magnetic field inclination angles play in the propagation characteristics of running penumbral waves…

Solar and Stellar Astrophysics · Physics 2015-06-17 D. B. Jess , V. E. Reznikova , T. Van Doorsselaere , P. H. Keys , D. H. Mackay

One of the greatest challenges in solar and stellar physics in coming years will be to observe the Second Solar Spectrum with a spatial resolution significantly better than 1 arcsec. This type of scattering polarization observations would…

Astrophysics · Physics 2009-11-13 Javier Trujillo Bueno , Nataliya Shchukina

We aim to characterise the small-scale magnetic fields for a sample of 16 Sun-like stars and investigate the capabilities of the newly upgraded near-infrared (NIR) instrument CRIRES$^+$ at the VLT in the context of small-scale magnetic…

We report on spectropolarimetric observations of a near-IR line of Mn I located at 15262.702 A whose intensity and polarization profiles are very sensitive to the presence of hyperfine structure. A theoretical investigation of the magnetic…

Two sequences of solar images obtained by the Transition Region and Coronal Explorer in three UV passbands are studied using wavelet and Fourier analysis and compared to the photospheric magnetic flux measured by the Michelson Doppler…

The solar magnetic fields emerging from the photosphere into the chromosphere and corona are comprised of a combination of "closed" and "open" fields. The closed magnetic field lines are defined as those having both ends rooted in the solar…

Solar and Stellar Astrophysics · Physics 2023-04-18 C. Nick Arge , Andrew Leisner , Samantha Wallace , Carl J. Henney

We present our findings on magnetar spectral line analysis in the context of upcoming high resolution, high effective area, high throughput X-ray telescopes for two cases: persistent magnetar emission and magnetar bursts. For magnetars in…

High Energy Astrophysical Phenomena · Physics 2023-03-15 Demet Kirmizibayrak , Jeremy Heyl

Studying the properties of the solar convection using high-resolution spectropolarimetry began in the early 90's with the focus on observations in the visible wavelength regions. Its extension to the infrared (IR) remains largely…

Solar and Stellar Astrophysics · Physics 2019-10-16 Ivan Milic , Smitha Narayanamurthy , Andreas Lagg

We present a novel experiment with the capacity to independently measure both the electron density and the magnetic field of the solar corona. We achieve this through measurement of the excess Faraday rotation due to propagation of the…

Astrophysics · Physics 2009-11-13 S. M. Ord , S. Johnston , J. Sarkissian

I review some recent advances in methods to diagnose polarized radiation with which we may hope to explore the magnetism of the solar chromosphere and corona. These methods are based on the remarkable signatures that the radiatively induced…

Solar and Stellar Astrophysics · Physics 2015-05-13 J. Trujillo Bueno

The measurement of Zeeman splitting in spectral lines---both in emission and absorption---can provide direct estimates of the magnetic field strength and direction in atomic and molecular clouds, both in our own Milky Way and in external…

The MHD virial theorem may be used to estimate the magnetic energy of active regions based on vector magnetic fields measured at the photosphere or chromosphere. However, the virial estimate depends on the measured vector magnetic field…

Astrophysics · Physics 2009-11-13 M. S. Wheatland , T. R. Metcalf