Sunspots are intense collections of magnetic fields that pierce through the Sun's photosphere, with their signatures extending upwards into the outermost extremities of the solar corona 1. Cutting-edge observations and simulations are providing insights into the underlying wave generation 2, configuration 3,4 and damping 5 mechanisms found in

Aims: We investigate the dynamics and magnetic properties of the plasma, including the line-of-sight velocity (LOS) and optical depth, as well as the vertical and horizontal magnetic fields, belonging to an erupted solar filament. Methods: The filament eruption was observed with the GREGOR Infrared Spectrograph at the 1.5-meter GREGOR telescope on

The nonlinear force-free field (NLFFF) modeling has been extensively used to infer the three-dimensional magnetic field in the solar corona. One of the assumptions in the NLFFF extrapolation is that the plasma beta is low, but this condition is considered to be incorrect in the photosphere. We examine direct measurements of the chromospheric

In three-dimensional (3D) radiative transfer (RT) problems, the tensor product quadratures are generally not optimal in terms of the number of discrete ray directions needed for a given accuracy of the angular integration of the radiation field. In this paper, we derive a new set of angular quadrature rules that are more suitable for solving 3D RT

We analyse the temporal evolution of the inclination component of the magnetic field vector for the penumbral area of 25 isolated sunspots. Compared to previous works, the use of data from the HMI instrument aboard the SDO observatory facilitates the study of a very long time series (≈1 week) with a good spatial and temporal resolution. We used the

We carry out a theoretical study of the polarization of the solar Mg II h-k doublet (including its extended wings) and the subordinate ultraviolet (UV) triplet around 280 nm. These lines are of great diagnostic interest, as they encode information on the physical properties of the solar atmosphere from the upper photosphere to the chromosphere

The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) sounding rocket experiment, launched in 2015 September, observed the hydrogen Lyα line (121.6 nm) in an unprecedented high temporal cadence of 0.3 s. CLASP performed sit-and-stare observations of the quiet Sun near the limb for 5 minutes with a slit perpendicular to the limb and successfully

We analyze high-resolution spectropolarimetric observations of a flux-emerging region (FER) in order to understand its magnetic and kinematic structure. Our spectropolarimetric observations in the He I 10830 Å spectral region of a FER were recorded with GRIS at the 1.5 m aperture GREGOR telescope. A Milne-Eddington-based inversion code was employed

Context. The analysis of waves on the visible side of the Sun allows the detection of active regions on the far side through local helioseismology techniques. Knowing the magnetism in the whole Sun, including the non-visible hemisphere, is fundamental for several space weather forecasting applications. Aims: Seismic identification of far-side

Context. Imaging spectrographs are popular instruments used to obtain solar data. They record quasi-monochromatic images at selected wavelength positions. By scanning the spectral range of the line, it is possible to obtain bidimensional maps of the field-of-view with a moderate spectral resolution. Aims: In this work, we evaluate the quality of

Aims: We derive information about the dynamics of the stellar photosphere, including pulsation, from a coherent interpretation of the linear polarisation detected in the spectral lines of the Mira star χ Cyg. Methods: From spectropolarimetric observations of χ Cyg, we performed a careful analysis of the polarisation signals observed in atomic and

Context. Because of the complex physics that governs the formation of chromospheric lines, interpretation of solar chromospheric observations is difficult. The origin and characteristics of many chromospheric features are, because of this, unresolved. Aims: We focus on studying two prominent features: long fibrils and flare ribbons. To model these

We report on spectropolarimetric observations across the Mg II h and k lines at 2800 Å made by the Ultraviolet Spectrometer and Polarimeter on board the Solar Maximum Mission satellite. Our analysis confirms the strong linear polarization in the wings of both lines observed near the limb, as previously reported, but also demonstrates the presence

In a recent paper, Zioutas and Valachovic (2018) claim that dark matter is responsible for a significant fraction of the melanoma skin cancer. This conclusion is drawn from their observation of a significant correlation between skin melanoma incidence in the US and the inner planets positions (especially those of Mercury and Earth). Here, I present

Waves and shocks traveling through the solar chromospheric plasma are influenced by its partial ionization and weak collisional coupling, and may become susceptible to multi-fluid effects, similar to interstellar shock waves. In this study, we consider fast magneto-acoustic shock wave formation and propagation in a stratified medium, that is

The three-dimensional (3D) shape of a galaxy inevitably is tied to how it has formed and evolved and to its dark matter halo. Local extremely metal-poor galaxies (XMPs; defined as having an average gas-phase metallicity <0.1 solar) are important objects for understanding galaxy evolution largely because they appear to be caught in the act of

Aims: We aim to investigate the validity of the weak field approximation (WFA) for determining magnetic fields in quiet regions of the solar photosphere using the polarization caused by the Zeeman effect in the Si I 10 827 Å line. Methods: We solved the NLTE line formation problem by means of multilevel radiative transfer calculations in a three

The linear polarization produced by scattering processes in the hydrogen Lyα line of the solar disk radiation is a key observable for probing the chromosphere–corona transition region (TR) and the underlying chromospheric plasma. While the line-center signal encodes information on the magnetic field and the three-dimensional structure of the TR

Solar chromosphere consists of a partially ionized plasma, which makes modeling the solar chromosphere a particularly challenging numerical task. Here we numerically model chromospheric waves using a two-fluid approach with a newly developed numerical code. The code solves two-fluid equations of conservation of mass, momentum, and energy, together

Context. The morphology of spectral line polarization is the most valuable observable to investigate the magnetic and dynamic solar atmosphere. However, in order to develop solar diagnosis, it is fundamental to understand the different kinds of anomalous solar signals that are routinely found in linear and circular polarization (LP,CP). Aims: We