Related papers: Temporal Relation between Disappearance of Penumbr…
Comparison of photographic observations and vector-magnetograph measurements demonstrate, that the outer boundary of the sunspot penumbra --even in complex sunspot groups-- closely follows the 0.075T isogauss line of the total value of the…
Prominences show a surprising amount of fine structure and it is widely believed that their threads, as seen in H$\alpha$ observations, provide indirect information concerning magnetic field topology. We investigate the spontaneous…
Observations of X-ray filaments attached to a couple of powerful pulsars suggest escape of TeV electrons and/or positrons (e$^{\pm}$) from pulsar bow shocks into surrounding large scale magnetic fields. These filaments are usually…
The flare-prolific active region NOAA 10930 offered both a developing delta-spot and a decaying satellite sunspot of opposite polarity. The objective of this study is to characterize the photometric decay of the satellite sunspot and the…
Sunspots are crucial for exploring how magnetic fields and plasma flows interact in the solar atmosphere, spanning from the stable photosphere to the shock-dominated chromosphere. To determine the thermal, magnetic, and kinematic properties…
A sunspot emanates from a growing pore or protospot. In order to trigger the formation of a penumbra, large inclinations at the outskirts of the protospot are necessary. The penumbra develops and establishes by colonising both umbral areas…
We report multi-wavelength ultraviolet observations taken with the IRIS satellite, concerning the emergence phase in the upper chromosphere and transition region of an emerging flux region (EFR) embedded in the unipolar plage of active…
The various mechanisms of magneto-convective energy transport determines the structure of sunspots and active regions. We characterise the appearance of light bridges and other fine-structure details and elaborate on their…
Aims. We analyse SUMER spectral scans of a large sunspot within active region NOAA 10923, obtained on 14-15 November 2006, to determine the morphology and dynamics of the sunspot atmosphere at different heights/temperatures. Methods: The…
Filamentary structures are ubiquitous in the interstellar medium, yet their formation, internal structure, and longevity have not been studied in detail. We report the results from a comprehensive numerical study that investigates the…
We investigate whether flux cancellation is responsible for the formation of a very massive filament resulting in the spectacular 2011 June 7 eruption. We analyse and quantify the amount of flux cancellation that occurs in NOAA AR 11226 and…
The aim of this work is the determination of the twist, writhe, and self magnetic helicity of penumbral filaments located in an inner Sunspot penumbra. To this extent, we inverted data taken with the spectropolarimeter (SP) aboard Hinode…
High-resolution imaging observations from the Hinode spacecraft in the CaII H line are employed to study the dynamics of the chromosphere above a sunspot. We find that umbral flashes and other brightenings produced by the oscillation are…
The temporal evolution of a solar prominence inserted in a three-dimensional magnetic flux rope is investigated numerically. Using the model of Titov Demoulin (1999) under the regime of weak twist, the cold and dense prominence counteracts…
We present observations of the eruption and then reformation of a filament caused by its nearby emerging magnetic flux. Driven by the emerging magnetic flux, the emerged positive fluxes moved toward and cancelled with its nearby negative…
We use spectro-polarimetric data recorded by Hinode to analyze the magnetic field configuration of a part of a sunspot (AR 10923) where a bundle of penumbral filaments are intruding into its umbra. We want to explore the role of the sunspot…
We employ high resolution filtergrams and polarimetric measurements from Hinode to follow the evolution of a sunspot for eight days starting on June 28, 2007. The imaging data were corrected for intensity gradients, projection effects, and…
Substructures - dark lanes and tails - of umbral dots (UDs) were predicted by numerical simulations of magnetoconvection. We analyse a 6 h 23 min time series of broadband images of a large umbra in the active region NOAA 10634, acquired…
Context. HI filaments are closely related to dusty magnetized structures that are observable in the far infrared (FIR). Recently it was proposed that the coherence of oriented HI structures in velocity traces the line of sight magnetic…
We study the evolution of a small-scale emerging flux region (EFR) in the quiet Sun, from its emergence to its decay. We track processes and phenomena across all atmospheric layers, explore their interrelations and compare our findings with…