English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Ellerman bombs (EBs) are short-lived and compact structures that are observedwell in the wings of the hydrogen H-alpha line. EBs are also observed in thechromospheric CaII lines and in UV continua. H-alpha line profiles of EBs showa deep absorption at the line center and enhanced emission in the line wings.Similar shapes of the line profiles are observed for the CaII IR line at 8542ang. It is generally accepted that EBs may be considered as compact microflareslocated in lower solar atmosphere. However, it is still not clear where exactlythe emission of EBs is formed in the solar atmosphere. High-resolutionspectrophotometric observations of EBs were used for determining of theirphysical parameters and construction of semi-empirical models. In our analysiswe used observations of EBs obtained in the H-alpha and CaII H lines. We alsoused NLTE numerical codes for the construction of grids of 243 semi-empiricalmodels simulating EBs structures. In this way, the observed emission could becompared with the calculated line spectra. For a specific model we foundreasonable agreement between the observed and theoretical emission and thus weconsider such model as a good approximation of the EBs atmospheres. This modelis characterized by an enhanced temperature in the lower chromosphere and canbe considered as a compact structure (hot spot). For the first time the set oftwo lines H-alpha and CaII H was used to construct semi-empirical models ofEBs. Our analysis shows that EBs can be described by a "hot spot" model, withthe temperature and/or density increase through a few hundred km atmosphericstructure. We confirmed that EBs are located close to the temperature minimumor in the lower chromosphere. Two spectral features, observed simultaneously,significantly strengthen the constraints on a realistic model.

Observations and NLTE modeling of Ellerman bombs