The sun provides an explosive, heavenly example of self-organized criticality. Sudden bursts of intense radiation emanate from rapid rearrangements of the magnetic field network in the corona. Avalanches are triggered by loops of flux that reconnect or snap into lower energy configurations when they are overly stressed. Our recent analysis of observational data reveals that the loops (links) an...

Cutting-edge observations with the 1.6-meter telescope at Big Bear Solar Observatory (BBSO) in California have taken research into the activity of the Sun to new levels of understanding of the structure and evolution of the solar atmosphere at high-resolution spatial and temporal scales. On August 7, 2013 the NST observed active region NOAA 11810 in photospheric and chromospheric wavelengths. T...

PICARD SOL is the ground component of the PICARD mission and is operational since March 2011. A set of instruments including the replica of the space instrument and several atmospheric monitors was set up at Calern observatory in order to compare solar radius measured in space and on ground and to better understand and calibrate atmospheric effects on ground based measurements. SODISM II provid...

Wecontinue studying the small-scale topologyof dynamical phenomena in the quiet-sun internetwork atmosphere through statistical estimation of the co-location probability of different fine-structure elements and wave modes. In this paper we chart spatial alignments between the granular brightness structuring of the photosphere, Ca ii K2V brightness patterns in the chromosphere, and wave amplitud...

We show that once a black hole surpasses some critical temperature Tcrit, the emitted Hawking radiation interacts with itself and forms a nearly thermal photosphere. Using QED, we show that the dominant interactions are bremsstrahlung and electronphoton pair production, and we estimate Tcrit ∼ me/α 5/2, which when calculated more precisely is found to be Tcrit ≈45 GeV. The formation of the phot...

The variation of the solar irradiance over the solar cycle has a strong wavelength dependence, being larger at shorter wavelengths. Here we present simple models of the spectral dependence of irradiance variations between solar activity maximum and minimum. We find that the observations (which concentrate on the UV) cannot be reproduced by a change in effective temperature of the Sun (or of par...

We give an explanation for the opposite sense of asymmetry of the solar acoustic mode lines in velocity and intensity oscillation power spectra, thereby solving the half-decade–old puzzle of Duvall and coworkers. The solution came after comparing the velocity and intensity oscillation data of medium angular degree l obtained from the Michelson Doppler Imager instrument on board the Solar and He...

We report on the discovery of mostly horizontal field channels just outside sunspot penumbrae (in the so-called ‘moat’ region) that are seen to sustain supersonic flows (line-of-sight component of 6 km s). The spectral signature of these supersonic flows corresponds to circular polarization profiles with an additional, satellite, third lobe of the same sign as the parent sunspot’ Stokes V blue ...

Recent observations indicate that solar p-mode line profiles are not exactly Lorentzian, but rather exhibit varying amounts of asymmetry about their respective peaks. We analyze p-mode line asymmetry using both a simplified one-dimensional model and a more realistic solar model. We find that the amount of asymmetry exhibited by a given mode depends on the location of the sources exciting the mo...