Tomasz Mrozek

Energy Release During Slow Long Duration Flares Observed by RHESSI

Slow long-duration events (SLDEs) are flares characterized by the long duration of their rising phase. In many such cases the impulsive phase is weak without typical short-lasting pulses. Instead, smooth, long-lasting hard X-ray (HXR) emission is observed. We analyzed hard X-ray emission and morphology of six selected SLDEs. In our analysis we utilized data from the RHESSI and GOES satellites. The physical parameters of HXR sources were obtained from imaging spectroscopy and were used for the energy balance analysis. The characteristic decay time of the heating rate, after reaching its maximum value, is very long, which explains the long rising phase of these flares.

On the fine structure of solar flare X-ray loop top sources

Solar flare X-ray loop top sources (LTSs) are known since early observations from 7 Skylab.They are always present accompanying long duration events (LDE), but their nature 8 remains unclear. One of the main unknowns is spatial structure of LTSs. Observations indicate 9 that LTSs are large and diffuse, but several authors suggested that there is present a fine, internal 10 structure within them which should be resolved even using present space instrumentation.We 11 present an example for the solar flare well observed by SDO/AIA and RHESSI. The LTS was 12 dynamic with an episode of splitting into two sources. We performed detailed analysis of X13 ray sources morphology using restored RHESSI images. Moreover, we conducted a number of 14 simulations taking into account various possible spatial distributions of X-ray emission. We have 15 found that in case of the flare investigated RHESSI should be capable to detect the fine structure 16 if present. However it is not visible on the restored images. Some of our simulations suggest that 17 we can also miss large, diffuse sources in the X-ray observations which may eventually lead to 18 misinterpretation of the observed X-ray features. 19

Searching for failed eruptions interacting with overlying magnetic field

It is well known that not all solar flares are connected with eruptions followed by coronal mass ejection (CME). Even strongest X-class flares may not be accompanied by eruptions or are accompanied by failed eruptions. One of important factor that prevent eruption from developing into CME is strength of the magnetic field overlying flare site. Few observations show that active regions with specific magnetic configuration may produce many CME-less solar flares. Therefore, forecasts of geoeffective events based on active region properties have to take into account probability of confining solar eruptions. Present observations of SDO/AIA give a chance for deep statistical analysis of properties of an active region which may lead to confining an eruption. We developed automated method which can recognize eruptions in AIA images. With this tool we will be able to analyze statistical properties of failed eruptions observed by AIA telescope.

Astro tourism: Astro Izery project

The Astro Izery project is carried by several institutions from Poland and Czech Republic. Its aim is to educate and inform tourists, who visit the Izery Mountains, about astronomy and light pollution. The project consists of two activities: permanent (sundials, planetary path etc.) and periodic (meetings, workshops). After five years the project is in good health and will gain more elements in next years.