Article
Astronomy & Astrophysics
M. Ellwarth, C. E. Fischer, N. Vitas, S. Schmiz, W. Schmidt
Summary: The study focuses on the movement characteristics of exploding granules, revealing that they can form new downflow lanes in interaction with the magnetic field. Additionally, the intensity and velocity oscillations of exploding granules in spectral lines display different temporal and spatial features, contributing to a better understanding of their formation and evolution processes.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
T. Roudier, M. Svanda, J. M. Malherbe, J. Ballot, D. Korda, Z. Frank
Summary: Observations and simulations have shown the existence of long-lasting downflows on the solar surface, which penetrate deep into the Sun, are filled with magnetic fields, and are connected with anchoring coronal loops. This suggests a link between downflows and coronal activity, with EUV cyclones potentially being an effective way to heat the corona.
ASTRONOMY & ASTROPHYSICS
(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
Abraham C-L Chian, Erico L. Rempel, Suzana S. A. Silva, Luis Bellot Rubio, Milan Gosic
Summary: The authors studied the spatiotemporal dynamics of vorticity and magnetic field in a photospheric vortex at a supergranular junction of the quiet Sun using Hinode's images. They observed intensified magnetic field at the centers of merging magnetic flux tubes trapped inside the vortex boundary during a 30-min interval of the vortex lifetime. They also found intensified electric current density at the interface boundary layers of merging tubes caused by strong vortical downflows. The study analyzed evidence of Lagrangian chaos and vortex stretching in the photospheric plasma turbulence, and reported the first solar observation of intensification of electromagnetic energy flux resulting from the merger of magnetic flux tubes.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
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
D. Calchetti, M. Stangalini, S. Jafarzadeh, G. Valori, K. Albert, N. Albelo Jorge, A. Alvarez-Herrero, T. Appourchaux, M. Balaguer Jimenez, L. R. Bellot Rubio, J. Blanco Rodriguez, A. Feller, A. Gandorfer, D. Germerott, L. Gizon, L. Guerrero, P. Gutierrez-Marques, J. Hirzberger, F. Kahil, M. Kolleck, A. Korpi-Lagg, A. Moreno Vacas, D. Orozco Suarez, I. Perez-Grande, E. Sanchis Kilders, J. Schou, U. Schuehle, J. Sinjan, S. K. Solanki, J. Staub, H. Strecker, J. C. del Toro Iniesta, R. Volkmer, J. Woch
Summary: In November 2021, Solar Orbiter began its nominal mission phase and gathered scientific data during three observation windows to study magnetohydrodynamic (MHD) wave modes in an active region using the spectropolarimetric capabilities of its instruments. The paper focuses on the analysis of a high-cadence dataset acquired by the High-Resolution Telescope (HRT) of the Polarimetric and Helioseismic Imager (SO/PHI) on board the Solar Orbiter. Various MHD modes at different frequencies are found to be excited in all studied structures, including sunspots and magnetic pores. The measurements from SO/PHI confirm the presence of magnetic and velocity oscillations consistent with MHD wave modes, but further improvements in modeling are needed to fully understand the relationship between different diagnostic fluctuations.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Vincent G. A. Boening, Aaron C. Birch, Laurent Gizon, Thomas L. Duvall
Summary: The research aimed to evaluate the validity of the existing upper limit of solar convective flow amplitudes at a depth of 0.96 solar radii using time-distance helioseismology and simplifying assumptions.
The results showed that the current procedure provides the correct order of magnitude of flow estimates for given flow fields, but may underestimate flow amplitudes at the largest scales by about two times.
It was concluded that the estimate obtained is indeed an upper limit when considering the scale dependence of the signal-to-noise ratio and the dependence of measurements on direction in Fourier space.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
C. J. Nelson, R. J. Campbell, M. Mathioudakis
Summary: High-amplitude oscillations in the LOS magnetic field strength were detected within a pore located in Active Region 12748, potentially caused by compression. Future research is needed to determine whether these oscillations are truly in the magnetic field strength at a specific depth in the solar atmosphere or if other effects are responsible.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
M. Stangalini, D. B. Jess, G. Verth, V. Fedun, B. Fleck, S. Jafarzadeh, P. H. Keys, M. Murabito, D. Calchetti, A. A. Aldhafeeri, F. Berrilli, D. Del Moro, S. M. Jefferies, J. Terradas, R. Soler
Summary: The study explores an unusual oscillation phenomenon in pores of sunspots, where a dominant frequency of 5 mHz is observed instead of the expected 3 mHz. By analyzing Doppler velocities and spectropolarimetry, researchers have identified distinct ridges in the B-omega diagram that are clear signatures of resonant magneto-hydrodynamic (MHD) oscillations confined within the pore umbra. This novel finding opens up a new avenue for identifying MHD wave modes in the umbral regions of both pores and sunspots.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Ryohtaroh T. Ishikawa, Motoki Nakata, Yukio Katsukawa, Youhei Masada, Tino L. Riethmueller
Summary: This article presents a new method based on deep neural networks to estimate the horizontal velocity of the photosphere. The method successfully predicts the horizontal velocities and evaluates the correlation coefficients at different spatial scales using a coherence spectrum.
ASTRONOMY & ASTROPHYSICS
(2022)
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
Yan-Xiao Liu, Chao-Wei Jiang, Ding Yuan, Ping-Bing Zuo, Wen-Da Cao
Summary: Investigating the length scales of granules helps to understand their dynamics in the photosphere. This study found that there is a critical size of 600 km that separates granules into two regimes: convection and turbulence. Granules larger than 600 km are dominated by convection, while smaller granules follow power-law distribution and are dominated by turbulence. The difference in granule behavior between active regions and quiet regions can be attributed to the interaction between fluid motions and strong magnetic fields. The presence of strong magnetic fields in active regions slows down the evolution of convective granules and leads to the formation of wide intergranular lanes.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
R. J. Campbell, S. Shelyag, C. Quintero Noda, M. Mathioudakis, P. H. Keys, A. Reid
Summary: This study aims to assess the accuracy of retrieving information about magnetic vectors in the internetwork photosphere using inversion techniques. Results show that depth-averaged parameters can be recovered accurately, and improvements in chi(2) value can be achieved by adding simple gradients to magnetic field strength, inclination, and line of sight velocity. The study demonstrates the essential symbiosis between realistic MHD simulations and observations in understanding the organization of magnetic fields in the internetwork photosphere.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
R. J. Campbell, M. Mathioudakis, M. Collados, P. H. Keys, A. Asensio Ramos, C. J. Nelson, D. Kuridze, A. Reid
Summary: The study reveals the presence of ubiquitous small-scale transverse magnetic fields in the quiet Sun internetwork region, which exhibit complex structures. High-resolution observations and magnetic inversion techniques can be used to characterize and track the dynamic evolution of these small-scale magnetic features.
ASTRONOMY & ASTROPHYSICS
(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
Takuma Matsumoto
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2016)
Article
Astronomy & Astrophysics
Takuma Matsumoto
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2018)
Article
Astronomy & Astrophysics
Takuma Matsumoto, Kazunari Shibata
ASTROPHYSICAL JOURNAL
(2010)
Article
Astronomy & Astrophysics
Y. Z. Zhang, K. Shibata, J. X. Wang, X. J. Mao, T. Matsumoto, Y. Liu, J. T. Su
ASTROPHYSICAL JOURNAL
(2012)
Article
Astronomy & Astrophysics
Takuma Matsumoto, Takeru Ken Suzuki
ASTROPHYSICAL JOURNAL
(2012)
Article
Astronomy & Astrophysics
T. Matsumoto, T. K. Suzuki
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2014)
Article
Astronomy & Astrophysics
Tetsu Anan, Reizaburo Kitai, Tomoko Kawate, Takuma Matsumoto, Kiyoshi Ichimoto, Kazunari Shibata, Andrew Hillier, Kenichi Otsuji, Hiroko Watanabe, Satoru UeNo, Shin'ichi Nagata, Takako T. Ishii, Hiroyuki Komori, Keisuke Nishida, Tahei Nakamura, Hiroaki Isobe, Masaoki Hagino
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN
(2010)
Article
Astronomy & Astrophysics
Kenichi Otsuji, Reizaburo Kitai, Takuma Matsumoto, Kiyoshi Ichimoto, Satoru UeNo, Shin'ichi Nagata, Hiroaki Isobe, Kazunari Shibata
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN
(2010)
Article
Astronomy & Astrophysics
Yuki Hashimoto, Reizaburo Kitai, Kiyoshi Ichimoto, Satoru UeNo, Shin'ichi Nagata, Takako T. Ishii, Masaoki Hagino, Hiroyuki Komori, Keisuke Nishida, Takuma Matsumoto, Kenichi Otsuji, Tahei Nakamura, Tomoko Kawate, Hiroko Watanabe, Kazunari Shibata
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN
(2010)
Article
Astronomy & Astrophysics
Takeru K. Suzuki, Shinsuke Imada, Ryuho Kataoka, Yoshiaki Kato, Takuma Matsumoto, Hiroko Miyahara, Saku Tsuneta
PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN
(2013)
Article
Astronomy & Astrophysics
Shota Chiba, Takeshi Imamura, Munetoshi Tokumaru, Daikou Shiota, Takuma Matsumoto, Hiroki Ando, Hiroshi Takeuchi, Yasuhiro Murata, Atsushi Yamazaki, Bernd Hausler, Martin Paetzold
Summary: The properties of the coronal plasma at different distances from the Sun were studied using radio-occultation observations. The study found differences in the solar wind velocity between the fast wind and slow wind, and detected quasi-periodic fluctuations in the electron density. It was also observed that the acoustic wave energy in the fast solar wind exceeds that in the slow wind.
Article
Astronomy & Astrophysics
T. Matsumoto, Y. Kawabata, Y. Katsukawa, H. Iijima, C. Quintero Noda
Summary: Chromospheric jets are possible carriers of energy and mass transport in the solar chromosphere, but their driving mechanisms are still unclear. In this study, we conducted a realistic radiative magnetohydrodynamics simulation and performed full Stokes synthesis to analyze the spectropolarimetric observations from the SUNRISE III balloon telescope. Our results suggest that the jet was launched by the collision between the transition region and an upflow driven by the twisted magnetic field. The predicted structure, time evolution, and Stokes signals will enhance the understanding of future spectropolarimetric observations with SUNRISE III/SCIP.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
Shinsuke Takasao, Takuma Matsumoto, Naoki Nakamura, Kazunari Shibata
ASTROPHYSICAL JOURNAL
(2015)
Proceedings Paper
Energy & Fuels
Takuma Matsumoto, Takeru Ken Suzuki
PROCEEDINGS OF THE THIRTEENTH INTERNATIONAL SOLAR WIND CONFERENCE (SOLAR WIND 13)
(2013)
Article
Astronomy & Astrophysics
Takuma Matsumoto
Summary: This study utilized a three-dimensional simulation to differentiate between heating mechanisms in the fast solar wind, confirming Alfven turbulence as the dominant heating mechanism in the acceleration region. Shock formation and phase mixing were also found to be important in the lower transition region.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)