Article
Astronomy & Astrophysics
Jiajia Liu, David Jess, Robert Erdelyi, Mihalis Mathioudakis
Summary: The collective and individual behavior of swirls in the solar atmosphere was studied. Two clusters of photospheric and chromospheric swirls with significant wavelet power were found, coinciding with the dominant period of the global p-mode spectrum. It is suggested that global p-modes may play an important role in triggering swirls and providing energy and mass fluxes to the upper solar atmosphere via the generation of swirls, Alfven pulses, and spicules.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
F. Schilliro, P. Romano
Summary: This study applies semantic segmentation using the self-organizing map technique to a high-resolution data set, successfully identifying and analyzing fine structures of solar activity, marking the first successful application of the SOM technique to astrophysical data sets.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Engineering, Aerospace
Hirdesh Kumar, Brajesh Kumar, S. P. Rajaguru
Summary: In this study, the propagation characteristics of atmospheric gravity waves under different magnetic field configurations in the solar atmosphere were investigated. It was found that magnetic fields have a suppressing and scattering effect on the propagation of gravity waves. These results are consistent with previous numerical simulations, suggesting that gravity waves are suppressed or scattered and reflected back into the lower solar atmosphere in the presence of magnetic fields. The observation of gravity waves is of great importance for understanding solar activity and atmospheric physics processes.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Astronomy & Astrophysics
Rayhane Sadeghi, Ehsan Tavabi
Summary: This investigation examines the oscillation periods of Mg ii k-line intensity, brightness temperature, and Doppler velocity above magnetic bright points (MBPs). Data from IRIS and SDO were analyzed, and MBPs were identified using Si iv slit-jaw images and magnetogram information from HMI. Network points were found to have a typical oscillation period of about 300 s, while internetwork points had an average oscillation period of about 180 s. Additionally, one BP showed intensity oscillation periods of 500 s, which are not related to commonly found oscillations in chromospheric/photospheric structures.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
A. Prasad, M. Ranganathan, C. Beck, D. P. Choudhary, Q. Hu
Summary: The study found that the inverse Evershed flow is driven along magnetic field lines connecting network elements with the outer penumbra, due to a gas pressure difference resulting from a difference in field strength. The gas pressure difference dominating the pressure force towards the inner foot points is primarily influenced by the difference in field strength.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Anjali J. Kaithakkal, J. M. Borrero, A. Pastor Yabar, J. de la Cruz Rodriguez
Summary: The study aims to quantify the conversion of magnetic to thermal energy during a quiet Sun cancellation event and investigate the resulting dynamics from the interaction of opposite-polarity magnetic features. Observations were made using imaging spectroscopy and spectropolarimetry to study a reconnection-related cancellation event and the appearance of a quiet Sun Ellerman bomb (QSEB). The study confirmed the release of magnetic energy during flux cancellation can support heating in the photosphere and lower chromospheric heights.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Larisa K. Kashapova, Anne-Marie Broomhall, Alena Larionova, Elena G. Kupriyanova, Ilya D. Motyk
Summary: The study investigates the decay phase of solar flares in multiple spectral bands, finding that the average flare profile observed in the 1700 angstrom channel decays more slowly than the average flare profile observed on the M4 dwarf, implying that M dwarf flare emission comes from a more dense layer. The cooling processes in solar flares were best described by the two exponents model, with the broken power-law model providing a good fit to the first decay phase but not to the second.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Multidisciplinary Sciences
Conor D. MacBride, David B. Jess, Samuel D. T. Grant, Elena Khomenko, Peter H. Keys, Marco Stangalini
Summary: A novel method using machine learning techniques is presented to identify and isolate the underlying components present in observed spectral lines, constraining their profiles through Voigt fits. The study validates the code's suitability for extracting two-component atmospheric profiles in sunspot chromospheres, achieving reliable results with median reduced chi (2) values equal to 1.03.
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2021)
Article
Astronomy & Astrophysics
A. Alharbi, I Ballai, V Fedun, G. Verth
Summary: In this study, we investigate the nature and characteristics of partially ionized plasma waves in the weakly ionized limit, which is typical for the lower part of the solar atmosphere. The plasma can be divided into two regions based on the magnitude of collisions between particles and collisional frequencies compared to the gyro-frequency of charged particles. In the non-magnetized solar photosphere, acoustic waves propagate with different damping rates determined by collisions with neutrals. In the weakly ionized chromosphere, only electrons are magnetized, and the two-fluid model is used to describe the dynamics influenced by electric currents created by disassociated charged particles.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Abbas Raboonik, Paul S. Cally
Summary: A 2.5D numerical model of magnetoacoustic-Alfven linear mode conversions in the partially ionized low solar atmosphere induced by the Hall effect is surveyed. It is found that the Hall effect has a significant impact on the conversion between magnetoacoustic and Alfven waves, especially in the low chromosphere.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Review
Astronomy & Astrophysics
David B. B. Jess, Shahin Jafarzadeh, Peter H. H. Keys, Marco Stangalini, Gary Verth, Samuel D. T. Grant
Summary: Waves and oscillations have been observed in the Sun's atmosphere for over half a century, but their role in supplying energy to the outermost extremities of the Sun's corona is still unknown. The lower solar atmosphere, specifically the photosphere and chromosphere, is of particular interest for studying the generation and propagation of energetic wave phenomena. Many ground-based and space-borne observing facilities are focusing on these regions to uncover the mechanisms behind these phenomena.
LIVING REVIEWS IN SOLAR PHYSICS
(2023)
Article
Astronomy & Astrophysics
David C. L. Millar, Lyndsay Fletcher, Ryan O. Milligan
Summary: The study found changes in the oscillatory structure of the chromosphere over a sunspot during the impulsive phase of an M1 flare, with oscillatory signals shifting in position and tending to increase in period. These results may be explained by a restructuring of the magnetic field in the chromosphere during flare activity.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
M. Pelekhata, K. Murawski, S. Poedts
Summary: Large-amplitude two-fluid Alfven waves can significantly contribute to the heating of the solar chromosphere and the generation of plasma outflows.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
X. Zhu, T. Wiegelmann
Summary: The aim of this study is to develop a fast and consistent extrapolation method for modeling multiple layers of the solar atmosphere. The new approach combines the magnetohydrostatic extrapolation with the nonlinear force-free field extrapolation, resulting in accurate and efficient reconstruction of the magnetic fields.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
K. Sowmya, A. Lagg, S. K. Solanki, J. S. Castellanos Duran
Summary: This study investigates the magnetized supersonic downflows in the chromosphere of the Sun, and finds their association with various features in the active regions. The draining of plasma along the legs of rising magnetic loops is identified as the most common mechanism for the supersonic downflows, which are found to exist above the subsonic component.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
M. Flores Soriano, K. G. Strassmeier, M. Weber
ASTRONOMY & ASTROPHYSICS
(2015)
Article
Astronomy & Astrophysics
M. Flores Soriano, K. G. Strassmeier, M. Weber
ASTRONOMY & ASTROPHYSICS
(2015)
Article
Astronomy & Astrophysics
M. Flores Soriano, K. G. Strassmeier
ASTRONOMY & ASTROPHYSICS
(2017)
Article
Astronomy & Astrophysics
N. Bello Gonzalez, M. Flores Soriano, F. Kneer, O. Okunev
ASTRONOMY & ASTROPHYSICS
(2009)
Article
Astronomy & Astrophysics
H. Korhonen, J. F. Gonzalez, M. Briquet, M. Flores Soriano, S. Hubrig, I. Savanov, T. Hackman, I. V. Ilyin, E. Eulaers, W. Pessemier
ASTRONOMY & ASTROPHYSICS
(2013)
Article
Astronomy & Astrophysics
M. Flores-Soriano, C. Cid, R. Crapolicchio
Summary: The ESA's SMOS mission investigates the potential utility of solar signals for scientific and space weather observations, finding that the SMOS Sun B-T can detect subtle variations in solar emissions, making it a promising tool for monitoring solar interferences and early assessment of flare geoeffectiveness. However, limitations in the current solar data from SMOS necessitate the development of a dedicated product for solar observations.
SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS
(2021)