Forschungs- & Entwicklungsinformationsdienst der Gemeinschaft - CORDIS

Final Activity Report Summary - SOND (Solar Network Dynamics)

The project focused on the coupling between network dynamics and fine structures seen in the solar chromosphere and transition region. The scientific objectives involved: (a) small-scale network dynamics, (b) leakage of photospheric oscillations to the chromosphere, and (c) nature of spicules.

The project realisation embraced organisation of joint observing campaigns aimed at acquisition of multispectral time sequences with long duration, their later analysis, interpretation, and confrontation with numerical simulations. The project realisation benefited from availability of unprecedented high-resolution image sequence, though brief, obtained in 2002 by the rocket-borne Very high Angular resolution ULtraviolet Telescope (VAULT). The researcher took part actively as a co-proposer and an observer in setup and execution of two joint observing programs with the titles: Dynamic fibrils in the upper photosphere, chromosphere, and above; and Spectroscopy of the quiet solar photosphere: properties of the shocks and the acoustic flux generation. The programs were accomplished successfully by the Vacuum Tower Telescope at Observatorio del Teide, Canary Islands, Spain in May and June 2008. Before the observing campaigns the researcher analyzed VAULT filtergrams in the Ly alpha spectral line searching for dynamic fibrils (DFs) - bright jet-like features emanating from network boundaries and displaying conspicuous extension and/or retraction on timescales of several seconds. The researcher developed a software for measuring of precise image coordinates facilitating first ever identification of DFs in Ly alpha.

The project brought the following results towards the objectives (a) and (b):
The observing campaigns provided extensive multispectral and spectropolarimetric data volumes sampling the solar atmosphere in infrared and visual spectral ranges from lower photosphere up to the upper chromosphere. Thorough interpretation is a formidable challenge extending beyond project duration. Nevertheless, samples of observations were already presented as image of the month July 2008 at the webpage of Kiepenheuer-Institut fur Sonnenphysik in Freiburg (KIS). They will be presented as a poster in 12th European Solar Physics Meeting (ESPM-12) in September 2008.

The project brought the following new results towards the objective (c):
1) most tops of DFs move supersonically;
2) decelerations of DFs vary from sub- to superballistic;
3) about half of DFs show outward acceleration, which may be an artefact from the poor sampling.

The similarity between these DFs observed in Ly alpha and the ones observed in Halpha suggests that the magnetoacoustic shock excitation proposed for the Halpha DFs is also valid for the Ly alpha ones. This supports an idea that Halpha and Ly alpha DFs are on-disk manifestation of limb spicules. The most important scientific achievement made by the project so far is the first ever identification of DFs in Ly alpha. This achievement was already presented at several scientific gatherings, submitted as a regular paper in Astronomy and Astrophysics and will be presented as a talk in ESPM-12.

The project outcomes are detailed in a publication accessed at URL by simply entering the researcher's name.

The project implementation also involved effective reintegration of the researcher after initial two-years MC Intra-European Fellowship back into his home country Slovakia via permanent employment at the Astronomical Institute, Slovak Academy of Sciences in Tatranska Lomnica (AISAS) located in Vychodne Slovensko (East Slovakia) and classified as less-favoured region of the Community. Simultaneously, the researcher maintained strong linkage and transfer of knowledge between AISAS and leading European institutions through research travels and stays thus enhancing the visibility of his research and home institute in European research area.

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