Related papers: Super Penumbral Chromospheric Flare
In the past two decades, the complex nature of sunspots has been disclosed with high-resolution observations. One of the most important findings is the "uncombed" penumbral structure, where a more horizontal magnetic component carrying most…
The extreme solar and SEP event of 20 January 2005 is analyzed from two perspectives. Firstly, we study features of the main phase of the flare, when the strongest emissions from microwaves up to 200 MeV gamma-rays were observed. Secondly,…
X-ray emission provides the most direct diagnostics of the energy-release process in solar flares. Occasionally, a superhot X-ray source is found to be above hot flare loops of ~10 MK temperature. While the origin of the superhot plasma is…
The generation of magnetic flux in the solar interior and its transport to the outer solar atmosphere will be in the focus of solar physics research for the next decades. One key-ingredient is the process of magnetic flux emergence into the…
Context. The origin of the heating of the solar atmosphere is still an unsolved problem. As the photosphere and chromosphere radiate more energy than the solar corona, it is challenging but important to reveal all the mechanisms that…
Fast magnetic reconnection powers explosive events throughout the universe, from gamma-ray bursts to solar flares. Despite its importance, the onset of astrophysical fast reconnection is the subject of intense debate and remains an open…
We analyze H-alpha images, soft X-ray profiles, magnetograms, extreme ultra-violet images and radio observations of two homologous flare events (M1.4/1N and M9.6/2B) on 20 November 2003 in the active region NOAA 10501 and study properties…
Recently, there have been some reports of unusually strong photospheric magnetic fields (which can reach values of over 7 kG) inferred from Hinode SOT/SP sunspot observations within penumbral regions. These superstrong penumbral fields are…
[Abridged] The magnetic and kinematic properties of the photospheric Evershed flow are relatively well known, but we are still far from a complete understanding of its nature. The evolution of the flow with time, which is mainly due to…
This paper investigates the temporal evolution of temperature, emission measure, energy loss and velocity in a C-class solar flare from both an observational and theoretical perspective. The properties of the flare were derived by following…
We present simultaneous photospheric and chromospheric observations of the trailing sunspot in NOAA 10904 during a weak flare eruption (GOES magnitude B7.8), obtained with the Swedish Solar Telescope (SST) in La Palma, Canary Islands.…
A supersonic flow of magnetized plasma is produced by the application of a 1 MA-peak, 500 ns current pulse to a cylindrical arrangement of parallel wires, known as an inverse wire array. The plasma flow is produced by the JxB acceleration…
The flows in and around sunspots are rich in detail. Starting with the Evershed flow along low-lying flow channels, which are cospatial with the horizontal penumbral magnetic fields, Evershed clouds may continue this motion at the periphery…
We report on the Atmospheric Imaging Assembly (AIA) observations of plasma outflows originating in a coronal dimming during the 2015 April 28th filament eruption. After the filament started to erupt, two flare ribbons formed, one of which…
We report on new spectro-polarimetric measurements with simultaneous filter imaging observation, revealing the frequent appearance of polarization signals indicating high-speed, probably supersonic, downflows that are associated with at…
Proper motions in a sunspot group with a delta-configuration and close to the solar disc center have been studied by employing local correlation tracking techniques. The analysis is based on more than one hour time series of G-band images.…
The EUV late phase is the second increase of the irradiance of the warm coronal lines during solar flares, and has a crucial impact on the Earth's ionosphere. In this paper, we report on the extremely energetic EUV late phase of a pair of…
I derived a geometrical model of the penumbral magnetic field topology from an uncombed inversion setup that aimed at reproducing the NCP of simultaneous spectra in near-IR (1.56 mu) and VIS (630 nm) spectral lines. I inverted the spectra…
We study the temporal evolution of downflows observed at the lateral edges of penumbral filaments in a sunspot located very close to the disk center. Our analysis is based on a sequence of nearly diffraction-limited scans of the Fe I 617.3…
The recently discovered gamma-ray flares from the Crab nebula are generally attributed to the magnetic energy release in a highly magnetized region within the nebula. I argue that such a region naturally arises in the polar region of the…