相关论文: Spectral Diagnostics of Active Prominences
The Extreme-ultraviolet Variability Experiment (EVE) onboard the Solar Dynamics Observatory (SDO) detects the solar EUV spectra with high temporal cadence and spectral resolution. The wavelength shifts of emission lines provide key…
A synthetic spectrum-fitting analysis was applied to the Ca II line at 3933.68 A for 122 A-type stars (7000 <Te < 10000 K) in a wide range of rotational velocity (10 < vsini < 300 km/s), in order to study the behaviors of Ca abundances…
Solar prominences are clouds of cool plasma levitating above the solar surface and insulated from the million-degree corona by magnetic fields. They form in regions of complex magnetic topology, characterized by non-potential fields, which…
We employ an automated detection algorithm to perform a global study of solar prominence characteristics. We process four months of TESIS observations in the He II 304 A line taken close to the solar minimum of 2008-2009 and focus mainly on…
Quantum interference effects play a vital role in shaping the linear polarization profiles of solar spectral lines. The Ba II D2 line at 4554 A is a prominent example, where the F-state interference effects due to the odd isotopes produce…
Effects of radio-frequency power and driven frequency on the two-dimensional (axial and radial) distributions of electron density and temperature were experimentally investigated in low pressure capacitively coupled argon plasmas. The…
Reliable nebular emission line diagnostics are essential for accurately inferring the physical properties (e.g. electron temperature, density, pressure, and metallicity) of H II regions from spectra. When interpreting spectra, it is typical…
The 1s2-1s2l lines are the most intense He-like ions lines. They are used as spectroscopic diagnostics for solar active regions as well as for different laboratory plasmas. Nowadays, it exits very high spectral resolution instruments and,…
In solar EUV spectra the He I and He II resonance lines show unusual behaviour and have anomalously high intensities compared with other transition region lines. The formation of the helium resonance lines is investigated through extensive…
Solar spicules are chromospheric fibrils that appear everywhere on the Sun, yet their origin is not understood. Using high resolution observations of spicules obtained with the Swedish 1-m Solar Telescope, we aim to understand how spicules…
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…
We present numerical simulations, obtained with the Versatile Advection Code, of the oscillations of an inverse polarity prominence. The internal prominence equilibrium, the surrounding corona and the inert photosphere are well represented.…
Aims: Out of a novel observing technique, we publish for the first time, SoHO-SUMER observations of the true spectral line profile of hydrogen Lyman-alpha in quiescent prominences. With SoHO not being in Earth orbit, our high-quality data…
A statistical study has been carried out of the relationship between plasma flow Doppler velocities and magnetic field parameters during the emergence of active regions at the solar photospheric level with data acquired by the Michelson…
Determining accurate plasma Doppler (line-of-sight) velocities from spectroscopic measurements is a challenging endeavour, especially when weak chromospheric absorption lines are often rapidly evolving and, hence, contain multiple spectral…
Context: Flux emergence in the solar atmosphere is a complex process that causes a release of magnetic energy as heat and acceleration of solar plasma at a variety of spatial scales. Methods: We analysed imaging spectropolarimetric data…
The first dedicated observation of an off-limb prominence by the Spectral Imaging of the Coronal Environment (SPICE) instrument took place on April 15, 2023. We aim to create parameter maps on the prominence region, including temperature,…
Prominences or filaments are cool clouds of partially ionized plasma living in the solar corona. Ground- and space-based observations have confirmed the presence of oscillatory motions in prominences and they have been interpreted in terms…
Models of the solar transition region made from lines other than those of helium cannot account for the strength of the helium lines. However, the collisional excitation rates of the helium resonance lines are unusually sensitive to the…
An analytical MHD model of a normal-polarity prominence with compressible flow is presented. The exact solution is constructed via a systematic nonlinear separation of variables method used to calculate several classes of MHD equilibria in…