Article
Astronomy & Astrophysics
Song Tan, Yuandeng Shen, Xinping Zhou, Zehao Tang, Chengrui Zhou, Yadan Duan, Surui Yao
Summary: We report the first observations of simultaneous large-amplitude longitudinal and transverse oscillations of a quiescent filament trigged by a two-sided-loop jet formed by the magnetic reconnection between the filament and an emerging loop in the filament channel, recorded by the Solar Dynamics Observatory and the Solar TErrestrial RElations Observatory.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
M. Luna, J. Terradas, J. Karpen, J. L. Ballester
Summary: The aim of this study is to understand the effects of nonuniform solar gravity on longitudinal oscillations and explore the validity of the pendulum model with different flux-tube geometries. The study finds that nonuniform gravity significantly modifies the pendulum model and introduces a cutoff period for longitudinal oscillations. Additionally, the study concludes that the corrected pendulum model is still valid for noncircular dips and is important for prominence seismology.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
I. I. Yakovkin, V. G. Lozitsky
Summary: We reviewed our previous results on this topic by expanding the wavelength range and analyzing a greater volume of observational data, including an X limb flare. By examining the active prominence and the limb flare, we found reliable and oppositely polarized secondary peaks in the V parameter. The observed spectral features suggest the presence of magnetic splitting and Doppler shift, with a magnetic field of approximately 2.2x10(5) G and a radial velocity of -46 km/s. However, alternative explanations involving weaker magnetic fields and significant macroscopic velocities were also considered.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2023)
Article
Astronomy & Astrophysics
M. Luna, J. R. Merou Mestre, F. Auchere
Summary: A new method for automatically detecting and parametrising oscillations in solar prominences using H-alpha data is proposed and validated through experiments. The method shows promising results in accurately identifying the periodic fluctuations in prominences and can contribute to a better understanding of their structure and evolution.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Y. W. Ni, J. H. Guo, Q. M. Zhang, J. L. Chen, C. Fang, P. F. Chen
Summary: This study investigates the decayless longitudinal filament oscillations through observations and numerical simulations. It is found that these oscillations are maintained by quasi-periodic jets and the period of oscillations depends not only on the pendulum model but also on the driving period of the jets.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Reetika Joshi, Manuel Luna, Brigitte Schmieder, Fernando Moreno-Insertis, Ramesh Chandra
Summary: This study presents two case studies that provide observational evidence in support of 2.5D numerical magnetohydrodynamics (MHD) experiments, showing that large-amplitude oscillations (LAOs) in filaments can be initiated by solar jets. Longitudinal magnetic field observations and analysis of brightness variations in H alpha observations reveal a quadrupolar configuration with an X-point at the top of the parasitic region suggestive of a classical null-point. The triggered LAOs have periods of around 70-80 min and are damped after a few oscillations.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
J. L. Ballester, R. Soler, M. Carbonell, J. Terradas
Summary: Partially ionized plasmas are commonly found in various astrophysical environments, with significant interest in solar physics. The study indicates that the adiabatic coefficient gamma or Gamma(1) depends on the ionization degree, particularly in solar partially ionized plasmas. The variations of Gamma(1) due to temperature, density, and ionization degree are crucial for determining the adiabatic sound speed and the period of slow waves in solar structures.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
V Jercic, R. Keppens, Y. Zhou
Summary: This study investigates the causal relations between a local energy release and a remote prominence oscillation with a realistic thread-like structure. The results show that the commonly used pendulum model is not sufficient to estimate the period of prominence oscillation accurately, and the influence of the energy source and the thread-like structure of the prominence needs to be considered.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
A. Alharbi, I Ballai, V Fedun, G. Verth
Summary: The study investigates the slow sausage waves in the solar atmosphere using a two-fluid model, focusing on the interaction between charged particles and neutrals. Results show that waves associated with charged particles are affected by gravitational stratification, while waves associated with neutrals are affected by wavelength.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
V. Jercic, R. Keppens
Summary: This study reveals the importance of random localized heating in the evolution of prominences and their threaded structure. Random heating strongly influences the morphology, area, mass, minimum temperature, and average density of prominence threads. Stronger heating sources can generate condensations faster and result in larger and more massive prominences. We also detail how stochastic heating sources determine counter-streaming flows and oscillations of prominence threads.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Yuhao Zhou, Xiaohong Li, Jie Hong, Rony Keppens
Summary: By simulating the formation process of solar filaments, a periodic phenomenon of appearing and disappearing was discovered, which is in good agreement with observations. This phenomenon can be explained by a forced oscillator model, and it was found that the stronger the heating or the higher the layer where the heating occurs, the more significant the effect appears.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Boris Filippov
Summary: This article discusses the evolution and height limitation of arcade flare loops. It is widely believed that the shape of eruptive prominences plays a crucial role in determining the ascension of the loops. The analysis is based on a simple rectangular circuit model.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
B. Filippov
Summary: The model of a partial current-carrying torus loop anchored to the photosphere is analyzed. Conditions leading to the catastrophic loss of equilibrium are considered, with the critical decay index of the external magnetic field found. The non-monotonous dependence of the critical decay index on the height of the apex and length of the flux rope is attributed to the line-tying conditions.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
B. Filippov
Summary: In this study, we numerically analyse a model of eruption of a thin flux rope with frozen endpoints in the photosphere. The parameters of the eruption depend on the initial length of the rope and its endpoints separation. The observations show that shorter filament eruptions are more often associated with flaring phenomena, while longer filament eruptions are more likely to be followed by coronal mass ejections (CMEs).
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
V Liakh, M. Luna, E. Khomenko
Summary: By using high-resolution numerical simulations, the study explores the attenuation and amplification mechanisms of large-amplitude longitudinal oscillations in solar prominences. The results indicate that the energy exchange between the bottom and top prominence regions is crucial for the attenuation and amplification of LALOs.
ASTRONOMY & ASTROPHYSICS
(2021)
Review
Astronomy & Astrophysics
T. Zaqarashvili, M. Albekioni, J. L. Ballester, Y. Bekki, L. Biancofiore, A. C. Birch, M. Dikpati, L. Gizon, E. Gurgenashvili, E. Heifetz, A. F. Lanza, S. W. McIntosh, L. Ofman, R. Oliver, B. Proxauf, O. M. Umurhan, R. Yellin-Bergovoy
Summary: Rossby waves are a common feature of large-scale motions in the Earth's atmosphere and oceans, as well as playing a significant role in various astrophysical objects. This paper reviews the theoretical and observational aspects of Rossby waves in different spatial and temporal scales in different astrophysical settings, discussing their physical role in various astrophysical processes. Possible future research directions in the theoretical and observational aspects of astrophysical Rossby waves are outlined in the paper.
SPACE SCIENCE REVIEWS
(2021)
Article
Astronomy & Astrophysics
Llorenc Melis, Roberto Soler, Jose Luis Ballester
Summary: Observational evidence shows the presence of small-amplitude transverse MHD waves in solar prominences, believed to be driven at the photosphere and dissipating as heat in the partially ionized plasma of the threads. The simple 1D model considered in this study suggests that MHD wave heating can play a significant role in energy balance within prominences, with further studies needed to explore this mechanism in more detail.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
M. Kriginsky, R. Oliver, P. Antolin, D. Kuridze, N. Freij
Summary: By utilizing high-resolution spectropolarimetric observations in the CaII 8542 angstrom line, we were able to infer information about the magnetic field in the low solar corona from coronal rain clumps. Our results show the omnipresence of magnetic field strengths of hundreds of Gauss, and even up to 1000 G, below 9 Mm from the visible limb. Additionally, we determined the temperature and microturbulent velocity differences between coronal rain clumps and off-limb spicules.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Roberto Soler, Jaume Terradas, Ramon Oliver, Jose Luis Ballester
Summary: The study shows that torsional Alfven waves driven in the photosphere can efficiently transmit energy to the coronal magnetic loop, with cavity resonances heavily affecting wave transmission. However, dissipation in the coronal plasma is weak, converting only a small percentage of energy into heat, which is insufficient to compensate for radiative losses. Most of the energy leaks back to the chromosphere, while dissipation is much more efficient in the lower atmosphere where wave heating can balance a significant fraction of radiation.
ASTROPHYSICAL JOURNAL
(2021)
Review
Astronomy & Astrophysics
A. K. Srivastava, J. L. Ballester, P. S. Cally, M. Carlsson, M. Goossens, D. B. Jess, E. Khomenko, M. Mathioudakis, K. Murawski, T. V. Zaqarashvili
Summary: This review focuses on the importance of the chromosphere in mass and energy transport within the solar atmosphere. It discusses the physics of magnetohydrodynamic waves and instabilities in large-scale chromospheric structures and magnetic flux tubes, and also highlights key observational aspects that aid in understanding the role of the solar chromosphere in various dynamic processes and wave phenomena. Additionally, the heating scenario of the solar chromosphere is examined, along with potential implications, future trends, and outstanding questions in this field.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Astronomy & Astrophysics
J. Terradas, M. Luna, R. Soler, R. Oliver, M. Carbonell, J. L. Ballester
Summary: The study investigates the oscillations and damping of solar prominence threads by understanding equilibrium solutions under different conditions and parameters. It explores the effects of multiple condensations along a magnetic field line and how partial ionization can modify thermal balance in the thread, affecting its length. The findings provide insights into the dynamics of prominence threads and their thermal behavior in the presence of radiative losses.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
J. Terradas, R. Soler, R. Oliver, P. Antolin, I. Arregui, M. Luna, I. Piantschitsch, E. Soubrie, J. L. Ballester
Summary: This article proposes several two-dimensional magnetohydrostatic equilibrium solutions to represent the magnetic structures of coronal holes and active regions. By simulating and calculating, a thermal structure similar to observations is obtained, and the influences of force balance and energy balance are studied. The results of this study are of great significance for our understanding of these structures in the solar atmosphere.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
J. L. Ballester, R. Soler, M. Carbonell, J. Terradas
Summary: Partially ionized plasmas are commonly found in various astrophysical environments, with significant interest in solar physics. The study indicates that the adiabatic coefficient gamma or Gamma(1) depends on the ionization degree, particularly in solar partially ionized plasmas. The variations of Gamma(1) due to temperature, density, and ionization degree are crucial for determining the adiabatic sound speed and the period of slow waves in solar structures.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
M. Luna, J. Terradas, J. Karpen, J. L. Ballester
Summary: The aim of this study is to understand the effects of nonuniform solar gravity on longitudinal oscillations and explore the validity of the pendulum model with different flux-tube geometries. The study finds that nonuniform gravity significantly modifies the pendulum model and introduces a cutoff period for longitudinal oscillations. Additionally, the study concludes that the corrected pendulum model is still valid for noncircular dips and is important for prominence seismology.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
V de Paula, J. J. Curto, R. Oliver
Summary: The heliophysics catalogues published by the Ebro Observatory during 1910-1937 have been converted into a digital format for studying the North-South (N-S) asymmetry of solar activity. The study reveals a cyclic behavior of solar activity with a preferred hemisphere changing systematically every 7.9 +/- 0.2 years.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Review
Astronomy & Astrophysics
Roberto Soler, Jose Luis Ballester
Summary: Partially ionized plasmas (PIP) are crucial components in various astrophysical environments, and their dynamics are influenced by the interactions between charged and neutral species. This review focuses on the theory of classic fluid instabilities in PIP, highlighting the unique effects of partial ionization. The onset and exponential growth of these instabilities are mathematically and theoretically investigated, and the results of nonlinear evolution from full numerical simulations are also discussed.
FRONTIERS IN ASTRONOMY AND SPACE SCIENCES
(2022)
Article
Astronomy & Astrophysics
David Kuridze, Petr Heinzel, Julius Koza, Ramon Oliver
Summary: In this study, off-limb emission of the lower solar atmosphere was investigated using high-resolution imaging spectroscopy. The results show that there is a dark intensity gap between the photospheric limb and chromosphere in the H beta line-wing images, which is absent in the Ca ii images. Synthetic spectra of the off-limb emissions were calculated and found to be in good agreement with the observations. The analysis of synthetic line profiles suggests that the observed gap in the H beta line-wing images maps the temperature minimum region between the photosphere and chromosphere. The observed gap was found to be located farther from the line core in the outer line-wing positions than in the synthetic profiles, indicating the need for an increased microturbulence in the model chromosphere to reproduce the dark gap. The temperature minimum also produces a small enhancement in synthetic Ca ii line-wing intensities, which is consistent with the observed enhancement below the temperature minimum layer in the off-limb Ca ii line-wing emissions.
ASTROPHYSICAL JOURNAL
(2022)
Article
Astronomy & Astrophysics
M. H. Ibanez, J. L. Ballester
Summary: Solar prominences are ionized plasma structures in the solar corona, and their oscillations have been observed and interpreted as MHD waves. This study investigates the temporal behavior of slow magnetoacoustic waves under heating-cooling imbalance, considering radiative losses, a general heating term, and partial ionization. The findings demonstrate a potential theoretical tool to explain small-amplitude oscillations in prominences.
Article
Astronomy & Astrophysics
David Kuridze, Hector Socas-Navarro, Julius Koza, Ramon Oliver
Summary: This study analyzed a solar spicule using high-resolution imaging spectroscopy, inverting the line profiles at different heights with a new version of non-LTE code NICOLE. By fitting observed spectral profiles at multiple heights, a double-component model with specific parameters was found to accurately reproduce the observed double-peak line profiles.
ASTROPHYSICAL JOURNAL
(2021)