Search Publications
Interferometric Observations of the Quiet Sun at 20 and 25 MHz in May 2014
Rucker, H. O.; Poedts, S.; Melnik, V. N. +3 more
We present the results of solar observations at 20 and 25 MHz with the Ukrainian T-shaped Radio telescope of the second modification (UTR-2) in the interferometric session from 27 May to 2 June 2014. In this case, the different baselines 225, 450, and 675 m between the sections of the east-west and north-south arms of UTR-2 were used. On 29 May 20…
Flare-related Recurring Active Region Jets: Evidence for Very Hot Plasma
Del Zanna, Giulio; Shimizu, Toshifumi; Mulay, Sargam M. +3 more
We present a study of two active region jets (AR jets) that are associated with two C-class X-ray flares. The recurrent, homologous jets originated from the northern periphery of a sunspot. We confirm flare-like temperatures at the footpoints of these jets using spectroscopic observations of Fe XXIII (263.76 Å) and Fe XXIV (255.11 Å) emission line…
Solar Models with Dynamic Screening and Early Mass Loss Tested by Helioseismic, Astrophysical, and Planetary Constraints
Guzik, Joyce A.; Wood, Suzannah R.; Mussack, Katie
The faint young Sun paradox remains an open question. Presented here is one possible solution to this apparent inconsistency, a more massive early Sun. Based on the conditions on early Earth and Mars, a luminosity constraint is set as a function of mass. We examine helioseismic constraints of these alternative mass-losing models. Additionally, we …
A Check on the Validity of Magnetic Field Reconstructions
Wheatland, M. S.; Gilchrist, S. A.; Mastrano, A.
We investigate a method to test whether a numerically computed model coronal magnetic field B departs from the divergence-free condition (also known as the solenoidality condition). The test requires a potential field B0 to be calculated, subject to Neumann boundary conditions, given by the normal components of the model field B at the …
Magnetic Lasso: A New Kinematic Solar Wind Propagation Method. Magnetic Lasso Propagation
Dósa, M.; Opitz, A.; Dálya, Z. +1 more
Solar wind propagation from the point of measurement to an arbitrary target in the heliosphere is an important input for heliospheric, planetary and cometary studies. In this paper a new kinematic propagation method, the magnetic lasso method is presented. Compared to the simple ballistic approach our method is based on reconstructing the ideal Pa…
Physical Properties of Umbral Dots Observed in Sunspots: A Hinode Observation
Mathew, Shibu K.; Yadav, Rahul
Umbral dots (UDs) are small-scale bright features observed in the umbral part of sunspots and pores. It is well established that they are manifestations of magnetoconvection phenomena inside umbrae. We study the physical properties of UDs in different sunspots and their dependence on decay rate and filling factor. We have selected high-resolution,…
Analysis of a Failed Eclipse Plasma Ejection Using EUV Observations
Koutchmy, S.; Tavabi, E.; Bazin, C.
The photometry of eclipse white-light (W-L) images showing a moving blob is interpreted for the first time together with observations from space with the PRoject for On Board Autonomy (PROBA-2) mission (ESA). An off-limb event seen with great details in W-L was analyzed with the SWAP imager (Sun Watcher using Active pixel system detector and image…
Solar Microflares Observed by SphinX and RHESSI
Mrozek, Tomasz; Kepa, Anna; Sylwester, Barbara +4 more
In 2009, the Russian Complex Orbital Observations Near-Earth of Activity of the Sun (CORONAS-Photon) spacecraft was launched, carrying the Polish Solar PHotometer In X-rays (SphinX). The SphinX was most sensitive in the spectral range 1.2 - 15 keV, thus an excellent opportunity appeared for comparison with the low-energy end of Ramaty High Energy …
A Long-Term Dissipation of the EUV He II (30.4 nm) Segmentation in Full-Disk Solar Images
Didkovsky, Leonid
Some quiet-Sun days observed by the Atmospheric Imaging Assembly (AIA) on-board the Solar Dynamics Observatory (SDO) during the time interval in 2010 - 2017 were used to continue our previous analyses reported by Didkovsky and Gurman (Solar Phys.289, 153, 2014a) and Didkovsky, Wieman, and Korogodina (Solar Phys.292, 32, 2017). The analysis consist…
Small-Scale Activity Above the Penumbra of a Fast-Rotating Sunspot
Bharti, L.; Sobha, B.; Quintero Noda, C. +3 more
High-resolution observations of small-scale activity above the filamentary structure of a fast-rotating sunspot of NOAA Active Region 10930 are presented. The penumbral filament that intrudes into the umbra shows a central dark core and substructures. It almost approached another end of the umbra, like a light bridge. The chromospheric Ca II H ima…