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The phenomena observed at the Sun have a variety of unique radio signatures that can be used to diagnose the processes in the solar atmosphere. The insights provided by radio obervations are further enhanced when they are combined with…

Solar and Stellar Astrophysics · Physics 2018-06-26 E. P. Kontar , A. Nindos

Our knowledge of the lower solar atmosphere is mainly obtained from spectropolarimetric observations, which are often carried out in the red or infrared spectral range and almost always cover only a single or a few spectral lines. Here we…

Instrumentation and Methods for Astrophysics · Physics 2019-01-30 T. L. Riethmüller , S. K. Solanki

Normal modes are coupled by the presence of perturbations in the Sun, providing a novel and under-appreciated helioseismic technique with which to image the solar interior. The process of measuring coupling between normal modes is…

Solar and Stellar Astrophysics · Physics 2018-07-18 Shravan Hanasoge

Remarkable progress has been made in understanding turbulent astrophysical plasmas in past decades including, notably, the solar wind and the interstellar medium. In the case of the solar wind, much of this progress has relied on in situ…

Solar and Stellar Astrophysics · Physics 2019-04-12 Tim Bastian , James Cordes , Justin Kasper , Adam Kobelski , Kelly Korreck , Gregory Howe , Steven Spangler , Chadi Salem , Angelos Vourlidas

The Atmospheric Imaging Assembly in the Solar Dynamics Observatory provides full Sun images every 1 seconds in each of 7 Extreme Ultraviolet passbands. However, for a significant amount of these images, saturation affects their most intense…

Instrumentation and Methods for Astrophysics · Physics 2015-09-02 Gabriele Torre , Richard A Schwartz , Federico Benvenuto , Anna Maria Massone , Michele Piana

In this work we use solar observations with the ALMA radio telescope at the wavelength of 1.21 mm. The aim of the analysis is to improve understanding of the solar chromosphere, a dynamic layer in the solar atmosphere between the…

Solar and Stellar Astrophysics · Physics 2018-12-19 R. Brajša , D. Sudar , I. Skokic , A. O. Benz , M. Kuhar , A. Kobelski , S. Wedemeyer , S. M. White , H. -G. Ludwig , M. Temmer , S. H. Saar , C. L. Selhorst

X-rays and gamma-rays from astronomical sources such as solar flares are mostly absorbed by the Earth's atmosphere. Resulting electron-ion production rate as a function of height depends on the intensity and wavelength of the injected…

Earth and Planetary Astrophysics · Physics 2016-04-27 Sourav Palit , Suman Ray , Sandip K. Chakrabarti

It is of great importance to monitor large solar active regions in the far-side of the Sun for space weather forecast, in particular, to predict their appearance before they rotate into our view from the solar east limb. Local…

Astrophysics · Physics 2009-11-13 Junwei Zhao

Large-scale velocity fields in the solar photosphere remain a mystery in spite of many years of intensive studies. In this thesis, the new method of the measurements of the solar photospheric flow fields is proposed. It is based on local…

Astrophysics · Physics 2007-12-13 Michal Svanda

Solar flares and plasma eruptions are sudden releases of magnetic energy stored in the plasma atmosphere. To understand the physical mechanisms governing their occurrences, three-dimensional magnetic fields from the photosphere up to the…

Solar and Stellar Astrophysics · Physics 2021-03-24 Takafumi Kaneko , Sung-Hong Park , Kanya Kusano

Long-term high-cadence measurements of stellar spectral variability are fundamental to better understand stellar atmospheric properties and stellar magnetism. These, in turn, are fundamental for the detectability of exoplanets as well as…

Instrumentation and Methods for Astrophysics · Physics 2023-05-16 S. Criscuoli , L. Bertello , D. P. Choudhary , M. DeLand , G. Kopp , A. Kowalski , S. Marchenko , K. Reardon , A. A. Pevtsov , D. Tilipman

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

The motions of the plasma and structures in and below the solar photosphere is not well understood. The results obtained using various methods cannot be in general considered as consistent, especially in details. In this contribution we…

Astrophysics · Physics 2008-09-30 M. Svanda , M. Klvana , M. Sobotka

The study of solar oscillations (helioseismology) has been a very successful method of researching the Sun. Helioseismology teaches us about the structure and mean properties of the Sun. Together with mid-resolution data, the local…

Solar and Stellar Astrophysics · Physics 2021-10-20 David Korda , Michal Švanda , Thierry Roudier

The Helioseismic Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) records line-of-sight Dopplergram images of convective flows on the surface. These images are used to obtain the multi-scale convective spectrum. We design…

Solar and Stellar Astrophysics · Physics 2021-08-09 Samarth G Kashyap , Shravan M Hanasoge

The efficient release of magnetic energy in astrophysical plasmas, such as during solar flares, can in principle be achieved through magnetic diffusion, at a rate determined by the associated electric field. However, attempts at measuring…

Observations show that propagating magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. The technique of MHD seismology uses the wave observations combined with MHD wave theory to indirectly infer physical parameters of…

Solar and Stellar Astrophysics · Physics 2015-06-11 M. Goossens , R. Soler , I. Arregui , J. Terradas

The consistency of time--distance inversions for horizontal components of the plasma flow on supergranular scales in the upper solar convection zone is checked by comparing the results derived using two k--\omega filtering procedures --…

Solar and Stellar Astrophysics · Physics 2015-06-16 Michal Svanda

Imaging systems based on a narrow-band tunable filter are used to obtain Doppler velocity maps of solar features. These velocity maps are created by taking the difference between the blue- and red-wing intensity images of a chosen spectral…

Solar and Stellar Astrophysics · Physics 2010-09-16 Sreejith Padinhatteeri , R. Sridharan , K. Sankarasubramanian

When inverting solar spectra, image degradation effects that are present in the data are usually approximated or not considered. We develop a data reduction method that takes these issues into account and minimizes the resulting errors. By…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 M. van Noort