Related papers: A Possible Selection Rule for Flares Causing Sunqu…
Solar flares are one of the most energetic events in the solar system, their impact on Earth at ground level and its atmosphere remains under study. The repercussions of this phenomenon in our technological infrastructure includes radio…
Quasi-periodic pulsations (QPP) are common in solar flares and are now regularly observed in stellar flares. We present the detection of two different types of QPP signals in the thermal emission light curves of the X9.3 class solar flare…
Recent results of a mixed shell model heated asymmetrically by transient increases in nuclear burning indicate the transient generation of small hot spots inside the Sun somewhere between 0.1 and 0.2 solar radii. These hot bubbles are…
We study the time evolution of Solar Flares activity by looking at the statistics of quiescent times $\tau_{L}$ between successive bursts. The analysis of 20 years of data reveals a power law distribution with exponent $\alpha \simeq 2.4$…
The solar corona has been revealed in the past decade to be a highly dynamic nonequilibrium plasma environment. Both the loop-filled coronal base and the extended acceleration region of the solar wind appear to be strongly turbulent, but…
Solar flares are transient yet dramatic events in the atmosphere of the Sun, during which a vast amount of magnetic energy is liberated. This energy is subsequently transported through the solar atmosphere or into the heliosphere, and…
Solar flares are the largest energy-release events in the Solar System, allowing us to study fundamental physical phenomena under extreme conditions. Those include magnetic reconnection, particle acceleration, radiation transport, and…
Solar oscillations consist of a rich spectrum of internal acoustic waves and surface gravity waves, stochastically excited by turbulent convection. They have been monitored almost continuously over the last ten years with high-precision…
On September 21, 2012, we carried out spectral observations of a solar facula in the Si I 10827 {\AA}, He I 10830 {\AA}, and H{\alpha} spectral lines. Later, in the process of analyzing the data, we found a small-scale flare in the middle…
Extreme space weather events including $\ge$X5.0 flares, ground level enhancement (GLE) events and super geomagnetic storms (Dst $\le$ -250 nT) caused by super active regions (SARs) during solar cycles 21-24 were studied. The total number…
The X-class solar flare of October 23, 2012, generated continuum photospheric emission and a strong helioseismic wave ("sunquake") that points to an intensive energy release in the dense part of the solar atmosphere. We study properties of…
There are still debates whether particle acceleration in solar flares may occur due to interruption of electric currents flowing along magnetic loops. To contribute to this problem, we performed the first statistical study of relationships…
Sequential chromospheric brightenings (SCBs) are often observed in the immediate vicinity of erupting flares and are associated with coronal mass ejections. Since their initial discovery in 2005, there have been several subsequent…
3-minute oscillations in the chromosphere are attributed to both slow magnetoacoustic waves propagating from the photosphere, and to oscillations generated within the chromosphere itself at its natural frequency as a response to a…
Ways to give medium- and short-term predictions of solar flares are proposed according to the statistical analysis of events during solar cycle 23. On one hand, the time distribution of both C and M class flares shows two main periods of…
The availability of continuous helioseismic data for two consecutive solar minima has provided a unique opportunity to study the changes in the solar interior that might have led to this unusual minimum. We present preliminary analysis of…
Energetic particle populations in the solar corona and in the heliosphere appear to have different characteristics even when produced in the same solar flare. It is not clear what causes this difference: properties of the acceleration…
We studied oscillations related to flare SOL2012-09-21T02:19 in the transition region and chromosphere based on Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) and Solar Dynamics Observatory (SDO) data, as well as data from a…
Torsional oscillations represent bands of fast and slow zonal flows around the Sun, which extend deep into the convection zone and migrate during solar cycles towards the equator following the sunspot butterfly diagram. Analysis of…
Using vector magnetograms obtained with the Spectro-polarimeter (SP) on aboard Hinode satellite, we studied two helicity parameters (local twist and current helicity) of 64 active regions occurred in the descending phase of solar cycle 23…