English
Related papers

Related papers: Spatial Distributions of Sunspot Oscillation Modes…

200 papers

The sunspots and other solar activity indicators tend to cluster on the surface of the Sun.These clusters very often occur at certain longitudes that persist in time.It is of general interest to find new and simple ways to characterize the…

Solar and Stellar Astrophysics · Physics 2015-05-14 J. Pelt , M. J. Korpi , I. Tuominen

For the first time, we have determined the spatial distribution of magnetic waveguides and resonant cavities at different heights in the sunspot atmosphere. We applied a decomposition of time cubes of EUV/UV sunspot images obtained in the…

Solar and Stellar Astrophysics · Physics 2025-02-21 Robert Sych

The subsurface structure of a solar sunspot is important in the stability of the sunspots and the energy transport therein. Two subsurface structure models have been proposed, the monolithic and cluster models, but no clear observational…

Solar and Stellar Astrophysics · Physics 2021-12-08 Kyuhyoun Cho , Jongchul Chae , Maria S. Madjarska

The observed splittings of solar oscillation frequencies can be employed to separate the effects of internal solar rotation and to estimate the contribution from a large-scale magnetic field or any latitude-dependent thermal perturbation…

Astrophysics · Physics 2007-05-23 H. M. Antia , S. M. Chitre , M. J. Thompson

Sunspots are known to be strong absorbers of solar oscillation modal power. The most convincing way to demonstrate this is done via Fourier-Hankel decomposition (FHD), where the local oscillation field is separated into in- and outgoing…

Solar and Stellar Astrophysics · Physics 2021-06-04 Matthias Waidele , Markus Roth , Gangadharan Vigeesh , Kolja Glogowski

A phenomenological relationship between oscillations in a sunspot and quasi-periodic pulsations in flaring energy releases at an active region above the sunspot, is established. The analysis of the microwave emission recorded by the…

Solar and Stellar Astrophysics · Physics 2015-05-19 R. Sych , V. M. Nakariakov , M. Karlicky , S. Anfinogentov

Differences between observed and theoretical eigenfrequencies of the Sun have characteristics which identify them as arising predominantly from properties of the oscillations in the vicinity of the solar surface: in the super-adiabatic,…

The observed properties (i.e., source size, source position, time duration, decay time) of solar radio emission produced through plasma processes near the local plasma frequency, and hence the interpretation of solar radio bursts, are…

The structure of the surface layers of the Sun is changed by magnetic activity which, in turn, changes the eigenfrequencies of the acoustic modes. These frequency shifts have been observed both in low- and high-degree data, and are found to…

Astrophysics · Physics 2007-05-23 M. Cunha , M. Bruggen , D. O. Gough

The solar torsional oscillations, i.e., the perturbations of the angular velocity of rotation associated with the eleven-year activity cycle, are a manifestation of the interaction among the interior magnetic fields, amplified and modulated…

Astrophysics · Physics 2009-11-13 Antonino F. Lanza

Context. One of the typical features shown by observations of solar prominence oscillations is that they are damped in time and that the values of the damping times are usually between one and three times the corresponding oscillatory…

Astrophysics · Physics 2009-11-13 R. Soler , R. Oliver , J. L. Ballester

It is well known that the dominant frequency of oscillations in the solar photosphere is $\approx$3 mHz, which is the result of global resonant modes pertaining to the whole stellar structure. However, analyses of the horizontal motions of…

Solar and Stellar Astrophysics · Physics 2024-07-08 M. Berretti , M. Stangalini , G. Verth , S. Jafarzadeh , D. B. Jess , F. Berrilli , S. D. T. Grant , T. Duckenfield , V. Fedun

The distribution of temperature and emission measure in the stationary heated solar atmosphere was obtained for the limiting cases of slow and fast heating, when either the gas pressure or the concentration are constant throughout the layer…

Solar and Stellar Astrophysics · Physics 2010-04-16 O. Ptitsyna , B. Somov

It has long been known that magnetic plage and sunspots are regions in which the power of acoustic waves is reduced within the photospheric layers. Recent observations now suggest that this suppression of power extends into the low…

Solar and Stellar Astrophysics · Physics 2015-06-19 Rekha Jain , Andrew Gascoyne , Bradley W. Hindman , Benjamin Greer

Waves and oscillations have been observed in the Sun's atmosphere for over half a century. While such phenomena have readily been observed across the entire electromagnetic spectrum, spanning radio to gamma-ray sources, the underlying role…

Solar and Stellar Astrophysics · Physics 2022-12-21 David B. Jess , Shahin Jafarzadeh , Peter H. Keys , Marco Stangalini , Gary Verth , Samuel D. T. Grant

The review addresses the spatial frequency morphology of sources of sunspot oscillations and waves, including their localization, size, oscillation periods, height localization with the mechanism of cut-off frequency that forms the observed…

Solar and Stellar Astrophysics · Physics 2016-03-09 Robert Sych

The energy balance in the corona of the Sun is the key to the long-standing coronal heating dilemma, which could be potentially revealed by observational studies of decayless kink oscillations of coronal plasma loops. A bundle of very long…

Solar and Stellar Astrophysics · Physics 2023-08-11 Sihui Zhong , Valery M. Nakariakov , Yuhu Miao , Libo Fu , Ding Yuan

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

Aims: To study the presence of superoscillations in coronal magnetoacoustic waves and its possible role in heating coronal loops through the strong and localized gradients they generate on the wave. Methods: An analytic model is built for…

Solar and Stellar Astrophysics · Physics 2018-07-04 A. López Ariste , M. Facchin

The frequencies of the solar acoustic oscillations vary over the activity cycle. The variations in other activity proxies are found to be well correlated with the variations in the acoustic frequencies. However, each proxy has a slightly…

Solar and Stellar Astrophysics · Physics 2016-12-07 A. R. G. Santos , M. S. Cunha , P. P. Avelino , W. J. Chaplin , T. L. Campante
‹ Prev 1 4 5 6 7 8 10 Next ›