Related papers: Measuring the solar atmosphere
Diagnostics for the solar chromosphere are relatively few compared to other parts of the atmosphere. Despite this, hundreds of Rydberg lines emitted by neutrals in this region have been observed at UV wavelengths. Here, we investigate their…
The solar convection manifests as granulation and intergranulation at the solar surface. In the photosphere, convective motions induce differential Doppler shifts to spectral lines. The observed convective blueshift varies across the solar…
Numerical simulations of the solar chromosphere have become increasingly realistic over the past 5 years. However, many observed chromospheric structures and behavior are not reproduced. Current models do not show fibrils in Ca II 8542, and…
A giant, quiet-Sun filament was observed with the high-resolution Echelle spectrograph at the Vacuum Tower Telescope at Observatorio del Teide on 2011 November 15. A mosaic of spectra (10 maps of 100" X 182") was recorded simultaneously in…
This paper investigates the distribution of linear polarization signals in the quiet Sun internetwork using ultra-deep spectropolarimetric data. We reduce the noise of the observations as much as is feasible by adding single-slit…
This paper shows the first synthetic tomography of the quiet solar chromosphere formed by spatial maps of scattering polarization. It has been calculated for the CaII 8498, 8542 and 3934 A lines by solving the NLTE (non-local…
We use state-of-the-art, three-dimensional non-local thermodynamic equilibrium (non-LTE) radiative magnetohydrodynamic simulations of the quiet solar atmosphere to carry out detailed tests of chromospheric magnetic field diagnostics from…
Context. Solar flux atlases observe the spatially integrated light from the Sun, treating it as a star. They are fundamental tools for gaining insight into the composition of the Sun and other stars, and are utilized as reference material…
The solar chromosphere is a transition layer between the cool, dense photosphere and the hot, rarefied corona. This boundary region plays a key role in regulating energy transport and structuring the magnetic field throughout the solar…
The polarization of the Mg II h & k resonance lines is the result of the joint action of scattering processes and the magnetic field induced Hanle, Zeeman, and magneto-optical effects, thus holding significant potential for the diagnostic…
The Ca II H & K lines are strong chromospheric diagnostics that can be used to determine the temperature stratification and magnetic structure of the solar atmosphere. The Atacama Large Millimetre/Submillimetre Array (ALMA) offers…
The Visible-light Imager and Magnetograph (VIM) proposed for the ESA Solar Orbiter mission will observe a photospheric spectral line at high spatial resolution. Here we simulate and interpret VIM measurements. Realistic MHD models are used…
We discuss spectropolarimetric measurements of photospheric (Fe I 630.25 nm) and chromospheric (Ca II 854.21 nm) spectral lines. Our long-term goal is to diagnose properties of the magnetic field near the base of the corona. We compare…
Synthetic observations produced from radiative magnetohydronamic simulations have predicted that higher polarization fractions in the quiet solar photosphere would be revealed by increasing the total integration time of observations at…
The morphology of circular polarisation profiles from solar spectropolarimetric observations encode information about the magnetic field strength, inclination, and line-of-sight velocity gradients. Previous studies used manual methods or…
We study the radiative emission of various types of solar features, such as quiet Sun, enhanced network, plage, and bright plage regions, identified on filtergrams taken in the Ca II K line. We analysed fulldisk images obtained with the…
The inference of the underlying state of the plasma in the solar chromosphere remains extremely challenging because of the nonlocal character of the observed radiation and plasma conditions in this layer. Inversion methods allow us to…
Context. The radiative losses in the solar chromosphere vary from 4~kW~m$^{-2}$ in the quiet Sun, to 20~kW~m$^{-2}$ in active regions. The mechanisms that transport non-thermal energy to and deposit it in the chromosphere are still not…
We study the structure of the photospheric magnetic field of the quiet Sun by investigating weak spectro-polarimetric signals. We took a sequence of Stokes spectra of the Fe I 630.15 nm and 630.25 nm lines in a region of quiet Sun near the…
Solar observations at sub-mm, mm and cm wavelengths offer a straightforward diagnostic of physical conditions in the solar atmosphere because they yield measurement of brightness temperature which, for optically thick features, equals…