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The observed solar oscillation spectrum is influenced by internal perturbations such as flows and structural asphericities. These features induce splitting of characteristic frequencies and distort the resonant-mode eigenfunctions. Global…

Solar and Stellar Astrophysics · Physics 2023-04-26 Srijan Bharati Das , Samarth G. Kashyap , Deniz Oktay , Shravan M. Hanasoge , Jeroen Tromp

Aims: The primary objective of this study is to search for and identify wave modes within a sunspot penumbra. Methods: Infrared spectropolarimetric time series data are inverted using a model comprising two atmospheric components in each…

Astrophysics · Physics 2007-07-23 D. S. Bloomfield , S. K. Solanki , A. Lagg , J. M. Borrero , P. S. Cally

We use the three-dimensional hydrodynamic code of Stein and Nordlund to realistically simulate the upper layers of the solar convection zone in order to study physical characteristics of solar oscillations. Our first result is that the…

Astrophysics · Physics 2009-10-31 D. Georgobiani , A. G. Kosovichev , R. Nigam , A. Nordlund , R. F. Stein

Observations of the sun suggest that solar activities systematically create north-south hemispheric asymmetries. For instance, the hemisphere in which the sunspot activity is more active tends to switch after the early half of each solar…

Solar and Stellar Astrophysics · Physics 2017-04-12 D. Syukuya , K. Kusano

A variety of nonthermal characteristics like kinetic, e.g., temperature, anisotropies and suprathermal populations (enhancing the high energy tails of the velocity distributions) are revealed by the in-situ observations in the solar wind…

Solar and Stellar Astrophysics · Physics 2016-12-06 S. M. Shaaban , M. Lazar , S. Poedts , A. Elhanbaly

Spatial heterogeneity and temporal variability are general features in planetary weather and climate, due to the effects of planetary rotation, uneven stellar flux distribution, fluid motion instability, etc. In this study, we investigate…

Earth and Planetary Astrophysics · Physics 2021-08-02 Xinyi Song , Jun Yang

Recombination line profile shapes are derived for ionized spherical stellar winds at radio wavelengths. It is assumed that the wind is optically thick owing to free-free opacity. Emission lines of arbitrary optical depth are obtained…

Solar and Stellar Astrophysics · Physics 2018-11-07 R Ignace

The duration of activity growths in solar cycles is on average shorter than the duration of its declines. This asymmetry can result from fluctuations in dynamo parameters. A solar dynamo model with fluctuations in the $\alpha$-effect shows…

Solar and Stellar Astrophysics · Physics 2018-11-07 Leonid Kitchatinov , Alexander Nepomnyashchikh

We present new results on the structure of the solar core, obtained with new sets of frequencies of solar low-degree p modes obtained from the BiSON network. We find that different methods used in extracting the different sets of…

Solar and Stellar Astrophysics · Physics 2009-07-22 Sarbani Basu , William J. Chaplin , Yvonne Elsworth , Roger New , Aldo M. Serenelli

I present a matched-wave asymptotic analysis of the driving of solar oscillations by a general localised source. The analysis provides a simple mathematical description of the asymmetric peaks in the power spectrum in terms of the relative…

Astrophysics · Physics 2009-10-30 Colin S. Rosenthal

We investigate the origin of asymmetry in the measured current-voltage (I-V) characteristics of molecules with no inherent spatial asymmetry. We establish that such molecules can exhibit asymmetric I-V characteristics due to unequal…

Mesoscale and Nanoscale Physics · Physics 2016-08-31 Avik W. Ghosh , Ferdows Zahid , Prashant S. Damle , Supriyo Datta

Time-reversal symmetry enables shaping input waves to control output waves in many linear and nonlinear systems; however energy dissipation violates such symmetry. We consider a saturated multimode fiber amplifier in which light generates…

Optics · Physics 2024-02-19 Chun-Wei Chen , Kabish Wisal , Mathias Fink , A. Douglas Stone , Hui Cao

Observations reveal an increase with height of the line width of several coronal spectral lines probably caused by outwardly propagating Alfv{\'e}n waves. However, the spectral line width sometimes shows a sudden decrease at a height…

Astrophysics · Physics 2008-11-26 T. V. Zaqarashvili , R. Oliver , J. L. Ballester

We describe a global parametric model for the observed power spectra of solar oscillations of intermediate and low degree. A physically motivated parameterization is used as a substitute for a direct description of mode excitation and…

Solar and Stellar Astrophysics · Physics 2015-06-17 Sergei V. Vorontsov , Stuart M. Jefferies

Oscillations were observed across the whole solar disk using the Doppler shift and line depth of spectral lines from the CO molecule near 4666~nm with the National Solar Observatory's McMath/Pierce solar telescope. Power, coherence, and…

Solar and Stellar Astrophysics · Physics 2015-05-20 Matthew Penn , Tom Schad , Erin Cox

Ring diagram analysis can be used to study large scale velocity fields in the outer part of the solar convection zone. All previous works assume that the peak profiles in the solar oscillation power spectrum are symmetric. However, it has…

Astrophysics · Physics 2009-10-31 Sarbani Basu , H. M. Antia

Calculations of spectral darkening and visibility functions for the brightness oscillations of the Sun resulting from global solar oscillations are presented. This has been done for a broad range of the visible and infrared continuum…

Astrophysics · Physics 2008-03-11 C. Nutto , M. Roth , Y. Zhugzhda , J. Bruls , O. von der Lühe

The frequency spectrum of the hemispheric asymmetry of solar activity shows enhanced power for the period ranges around 8.5 years and between 30 and 50 years. This can be understood as the sum and beat periods of the superposition of two…

Solar and Stellar Astrophysics · Physics 2018-10-17 M. Schüssler , R. H. Cameron

According to a recent ray-based asymptotic theory, the high-frequency p-mode spectrum of rapidly rotating stars is a superposition of frequency subsets associated with dynamically independent regions of the ray-dynamics phase space. At high…

Solar and Stellar Astrophysics · Physics 2015-05-20 F. Lignieres , B. Georgeot , J. Ballot

Recent revisions of the determination of the solar composition have resulted in solar models in marked disagreement with helioseismic inferences. The effect of the composition change on the model is largely caused by the change in the…