Search Publications
Partial redistribution in 3D non-LTE radiative transfer in solar-atmosphere models
Leenaarts, Jorrit; Sukhorukov, Andrii V.
Context. Resonance spectral lines such as H I Ly α, Mg II H&K, and Ca II H&K that form in the solar chromosphere, are influenced by the effects of 3D radiative transfer as well as partial redistribution (PRD). So far no one has modeled these lines including both effects simultaneously owing to the high computing demands of existing algorit…
Compact solar UV burst triggered in a magnetic field with a fan-spine topology
Peter, H.; Chitta, L. P.; Young, P. R. +1 more
Context. Solar ultraviolet (UV) bursts are small-scale features that exhibit intermittent brightenings that are thought to be due to magnetic reconnection. They are observed abundantly in the chromosphere and transition region, in particular in active regions.
Aims: We investigate in detail a UV burst related to a magnetic feature that is adv…
Observations of Ellerman bomb emission features in He I D3 and He I 10 830 Å
Joshi, Jayant; Leenaarts, Jorrit; Libbrecht, Tine +2 more
Context. Ellerman bombs (EBs) are short-lived emission features, characterised by extended wing emission in hydrogen Balmer lines. Until now, no distinct signature of EBs has been found in the He I 10 830 Å line, and conclusive observations of EBs in He I D3 have never been reported.
Aims: We aim to study the signature of EBs in ne…
Excitation and evolution of vertically polarised transverse loop oscillations by coronal rain
Kohutova, P.; Verwichte, E.
Context. Coronal rain is composed of cool dense blobs that form in solar coronal loops and are a manifestation of catastrophic cooling linked to thermal instability. The nature and excitation of oscillations associated with coronal rain is not well understood.
Aims: We consider observations of coronal rain in a bid to elucidate the excitation…
Reconstruction of a helical prominence in 3D from IRIS spectra and images
Schmieder, B.; Labrosse, N.; López Ariste, A. +3 more
Context. Movies of prominences obtained by space instruments e.g. the Solar Optical Telescope (SOT) aboard the Hinode satellite and the Interface Region Imaging Spectrograph (IRIS) with high temporal and spatial resolution revealed the tremendous dynamical nature of prominences. Knots of plasma belonging to prominences appear to travel along both …
Cool and hot emission in a recurring active region jet
Del Zanna, Giulio; Mulay, Sargam M.; Mason, Helen
Aims: We present a thorough investigation of the cool and hot temperature components in four recurring active region jets observed on July 10, 2015 using the Atmospheric Imaging Assembly (AIA), X-ray Telescope (XRT), and Interface Region Imaging Spectrograph (IRIS) instruments.
Methods: A differential emission measure (DEM) analysis was …
Solar Hα features with hot onsets. II. A contrail fibril
Rouppe van der Voort, L. H. M.; Rutten, R. J.
The solar chromosphere observed in Hα consists mostly of narrow fibrils. The longest typically originate in network or plage and arch far over adjacent internetwork. We use data from multiple telescopes to analyze one well-observed example in a quiet area. It resulted from the earlier passage of an accelerating disturbance in which the gas was hea…
Comparing UV/EUV line parameters and magnetic field in a quiescent prominence with tornadoes
Fletcher, L.; Schmieder, B.; Labrosse, N. +2 more
Context. Understanding the relationship between plasma and the magnetic field is important for describing and explaining the observed dynamics of solar prominences.
Aims: We determine if a close relationship can be found between plasma and magnetic field parameters, measured at high resolution in a well-observed prominence.
Methods: A pr…
Synthetic IRIS spectra of the solar transition region: Effect of high-energy tails
Vocks, C.; Dzifčáková, E.; Dudík, J.
Aims: The solar transition region satisfies the conditions for presence of non-Maxwellian electron energy distributions with high-energy tails at energies corresponding to the ionization potentials of many ions emitting in the extreme-ultraviolet and ultraviolet portions of the spectrum.
Methods: We calculate the synthetic Si iv, O iv, a…
Chromospheric impact of an exploding solar granule
Bello González, N.; Rezaei, R.; Fischer, C. E.
Context. Observations of multi-wavelength and therefore height-dependent information following events throughout the solar atmosphere and unambiguously assigning a relation between these rapidly evolving layers are rare and difficult to obtain. Yet, they are crucial for our understanding of the physical processes that couple the different regimes …