Results 11 to 20 of about 14,551 (173)

Large Photospheric Doppler Shift in Solar Active Region 12673. I. Field-aligned Flows [PDF]

The Astrophysical Journal, 2023
Delta ( δ ) sunspots sometimes host fast photospheric flows along the central magnetic polarity inversion line (PIL). Here we study the strong Doppler shift signature in the central penumbral light bridge of solar active region NOAA 12673.
Jiayi Liu, Xudong Sun, Peter W. Schuck, Sarah A. Jaeggli, Brian T. Welsch, C. Quintero Noda   +5 more
doaj   +4 more sources

Video Magnetic Field and Velocity Fields of Solar Flares and Relative Active Region [PDF]

International Astronomical Union Colloquium, 1989
By means of Solar Magnetic Field Telescope, the fine structure of video magnetic fields (5324A) and sight-of-line velocity fields (4861A) of flare active region on July 23 (E53, S19) and Aug. 8(W25, S28) in 1987 has been obtained. The main characters are following:1.
Ai Guoxiang, Li Jing
openaire   +2 more sources

Average solar active region [PDF]

Astronomy & Astrophysics
Aims. Solar active regions (ARs) are key manifestations of the Sun’s magnetic activity, displaying diverse spatial and temporal characteristics. Their formation and evolution play a crucial role in understanding the solar dynamo and space weather. While individual ARs exhibit significant variability, ensemble averaging offers a method to extract their ...
Michal Švanda, Jan Jurčák, Markus Schmassmann   +2 more
openaire   +4 more sources

Flows and Nonthermal Velocities in Solar Active Regions Observed with the EUV Imaging Spectrometer onHinode: A Tracer of Active Region Sources of Heliospheric Magnetic Fields? [PDF]

The Astrophysical Journal, 2008
From Doppler velocity maps of active regions constructed from spectra obtained by the Extreme-ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft we observe large areas of outflow (20-50 km/s) that can persist for at least a day. These outflows occur in areas of active regions that are faint in coronal spectral lines formed at typical quiet
Doschek, G. A., Warren, H. P., Mariska, J. T., Muglach, K., Culhane, J. L., Hara, H., Watanabe, T   +6 more
openaire   +4 more sources

The active region source of a type III radio storm observed by Parker Solar Probe during encounter 2 [PDF]

Astronomy & Astrophysics, 2021
Context. We investigated the source of a type III radio burst storm during encounter 2 of NASA’s Parker Solar Probe (PSP) mission. Aims. It was observed that in encounter 2 of NASA’s PSP mission there was a large amount of radio activity and, in ...
L. Harra, D. Brooks, S. Bale, C. Mandrini, Krzysztof Barczynski, R. Sharma, S. Badman, S. Vargas Domínguez, M. Pulupa   +8 more
semanticscholar   +4 more sources

Solar photospheric spectrum microvariability [PDF]

Astronomy & Astrophysics
Context. Finding low-mass planets around solar-type stars requires understanding the physical variability of the host star, which greatly exceeds the planet-induced radial-velocity modulation.
Dravins Dainis, Ludwig Hans-Günter, Steffen Matthias, Allende Prieto Carlos, Koesterke Lars   +4 more
doaj   +2 more sources

Morphological variations of solar granules in the presence of magnetic fields [PDF]

Astronomy & Astrophysics
Context. Solar granulation consists of dynamic convective plasma cells that rise from the solar interior to the surface. The interaction between this plasma cells and the Sun’s magnetic field provides valuable insights into the dynamics of plasma near ...
Campos Rozo J. I., Jurčák J., Díaz Castillo S. M., van Noort M.   +3 more
doaj   +2 more sources

MHD Simulation of a Solar Eruption from Active Region 11429 Driven by a Photospheric Velocity Field

The Astrophysical Journal Letters, 2023
Abstract Data-driven simulation is becoming an important approach for realistically characterizing the configuration and evolution of solar active regions, revealing the onset mechanism of solar eruption events, and hopefully achieving the goal of accurate space weather forecasting, which is beyond the scope of any existing theoretical ...
Xinyi Wang, Chaowei Jiang, Xueshang Feng
openaire   +5 more sources

Horizontal flow fields in and around a small active region-- The transition period between flux emergence and decay [PDF]

, 2016
Aims. Combining high-resolution and synoptic observations aims to provide a comprehensive description of flux emergence at photospheric level and of the growth process that eventually leads to a mature active region. Methods.
M. Verma, C. Denker, H. Balthasar, C. Kuckein, S. J. G. Manrique, M. Sobotka, N. B. Gonz'alez, S. Hoch, A. Diercke, P. Kummerow, T. Berkefeld, M. Collados, A. Feller, A. Hofmann, F. Kneer, A. Lagg, J. Löhner-Böttcher, H. Nicklas, A. P. Yabar, A. P. Yabar, R. Schlichenmaier, Dirk Schmidt, W. Schmidt, M. Schubert, M. Sigwarth, S. Solanki, D. Soltau, J. Staude, K. Strassmeier, R. Volkmer, O. Lühe, T. Waldmann   +31 more
semanticscholar   +3 more sources

Toward a Robust Estimate of the Solar Photospheric Poynting Flux and Helicity Flux

The Astrophysical Journal
The observed solar photospheric magnetic fields and Doppler velocities are frequently used to quantify the Poynting flux and helicity flux. Multiple methods have been developed for this purpose, but their estimates of the Poynting flux and helicity flux ...
Jiayi Liu, Xudong Sun, Peter W. Schuck, Lars K. S. Daldorff   +3 more
doaj   +2 more sources