Related papers: Temperature diagnostics of chromospheric fibrils
CHROMIS, a new imaging spectrometer at the Swedish 1-m Solar Telescope (SST), can observe the chromosphere in the H and K lines of Ca II at high spatial and spectral resolution. Accurate modeling as well as an understanding of the formation…
Unipolar magnetic regions are often associated with supergranular cells. The chromosphere above these regions is regulated by the magnetic field, but the field structure is poorly known. In unipolar regions, the fibrillar arrangement does…
Solar chromospheric fibrils, as observed in the core of strong chromospheric spectral lines, extend from photospheric field concentrations suggesting that they trace magnetic field lines. These images have been historically used as proxies…
Solar pores are strongly magnetized regions lacking a photospheric penumbra and characterized by predominantly vertical magnetic fields. We present a multi-line study of flashes in a solar pore using high-resolution observations from the…
The strongly coupled hydrodynamic, magnetic, and radiation properties of the plasma in the solar chromosphere makes it a region of the Sun's atmosphere that is poorly understood. We use data obtained with the high-resolution Visible…
This review is split into two parts: one on chromospheric line formation in answer to the frequent question "where is my line formed", and one presenting state-of-the-art imagery of the chromosphere. In the first part I specifically treat…
We study non-LTE inversions of the Ca II infrared triplet lines as a tool for inferring physical properties of the quiet Sun. The inversion code is successful in recovering the temperature, velocity and longitudinal magnetic flux density in…
Most static 1D atmosphere models in the quiet Sun predict a rise of the gas temperature at chromospheric layers, but numerical simulations only yield an increase in the brightness temperature. We investigate the thermal structure in the…
In this study we explore the diagnostic potential of the chromospheric Ca II line at 8542A for studying the magnetic and dynamic properties of solar filaments. We have acquired high spatial resolution spectropolarimetric observations in the…
Numerical simulations of the solar chromosphere predict a diverse thermal structure with both hot and cool regions. Observations of plage regions in particular feature broader and brighter chromospheric lines, which suggest that they are…
We study chromospheric emission to understand the temperature stratification in the solar chromosphere. We observed the intensity profile of the CaIIH line in a quiet Sun region close to the disk center at the German Vacuum Tower Telescope.…
We study the polarization signals and physical parameters of penumbral microjets (PMJs) by using high spatial resolution data taken in the Fe I 630 nm pair, Ca II 854.2 nm and Ca II K lines with the CRISP and CHROMIS instruments at the…
(Abridged) Aims: In this paper, we seek to establish the suitability of imaging spectroscopy performed in the Ca II 854.2 nm line as a means to investigate the solar chromosphere at high resolution. Methods: We utilize monochromatic images…
Quiescent filaments appear as absorption features on the solar disk when observed in chromospheric lines and at continuum wavelengths in the millimeter (mm) range. Active region (AR) filaments are their small-scale, low-altitude analogues,…
Aims. We use advanced 3D NLTE radiative magnetohydrodynamic simulations of the solar atmosphere to carry out detailed tests of chromospheric diagnostics at millimeter and submillimeter wavelengths. Methods. We focused on the diagnostics of…
Observations of the solar chromosphere in the line-core of the \Halpha\ line show dark elongated structures called fibrils that show swaying motion. We performed a 3D radiation-MHD simulation of a network region, and computed synthetic…
The heating of the Sun's chromosphere remains poorly understood. While progress has been made on understanding what drives the quiet Sun internetwork chromosphere, chromospheric heating in strong magnetic field regions continues to present…
In order to enable high quality lens designs using calcium fluoride (CaF2) and Heraeus Infrasil 301 (Infrasil) for cryogenic operating temperatures, we have measured the absolute refractive index of these two materials as a function of both…
Chromospheric umbral oscillations produce periodic brightenings in the core of some spectral lines, known as umbral flashes. They are also accompanied by fluctuations in velocity, temperature, and, according to several recent works,…
Inversion codes allow reconstructing a model atmosphere from observations. With the inclusion of optically thick lines that form in the solar chromosphere, such modelling is computationally very expensive because a non-LTE evaluation of the…