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In a statistical analysis of Debrecen Photoheliographic Results sunspot area data we find that the logarithmic deviation (log D)' of the area decay rate D from the parabolic mean decay law (derived in the first paper in this series) follows…

Astrophysics · Physics 2015-06-24 K. Petrovay , V. Martinez-Pillet , L. van Driel-Gesztelyi

We used the Pixelised Wavelet Filtering (PWF) method to compute narrow-band power maps of SDO/AIA imaging datasets in the 1700 \AA{}, 1600 \AA{} and 304 \AA{} bandpasses that correspond to different heights. The cut-off frequency was…

Solar and Stellar Astrophysics · Physics 2014-04-15 Ding Yuan , R. Sych , V. E. Reznikova , V. M. Nakariakov

Aims. We seek indications or evidence of transmission/conversion of magnetoacoustic waves at the magnetic canopy, as a result of its impact on the properties of the wave field of the photosphere and chromosphere. Methods. We use…

Solar and Stellar Astrophysics · Physics 2015-11-30 Ioannis Kontogiannis , Georgia Tsiropoula , Kostas Tziotziou

Context: The interaction of plasma motions and magnetic fields is an important mechanism, which drives solar activity in all its facets. For example, photospheric flows are responsible for the advection of magnetic flux, the redistribution…

Solar and Stellar Astrophysics · Physics 2015-05-27 M. Verma , C. Denker

Context. Magnetic bright points (MBPs) are dynamic, small-scale magnetic elements often found with field strengths of the order of a kilogauss within intergranular lanes in the photosphere. Aims. Here we study the evolution of various…

We present high-precision spectro-polarimetric data with high spatial resolution (0.4$''$) of the very quiet Sun at 1.56$\mu$m obtained with the GREGOR telescope to shed some light on this complex magnetism. Half of our observed quiet-Sun…

We observed small scale magnetic flux emergence in a sunspot moat region by the Solar Optical Telescope (SOT) aboard the Hinode satellite. We analyzed filtergram images observed in the wavelengths of Fe 6302 angstrom, G-band and Ca II H. In…

Flare kernels are compact features located in the solar chromosphere that are the sites of rapid heating and plasma upflow during the rise phase of flares. An example is presented from a M1.1 class flare observed on 2011 February 16 07:44…

Solar and Stellar Astrophysics · Physics 2015-06-12 Peter Young , George Doschek , Harry Warren , Hiro Hara

Time-distance helioseismic measurements in surface- and deep-focus geometries for wave-paths that distinguish surface magnetic contributions from those due to deeper perturbations beneath a large sunspot are presented and analysed. Travel…

Astrophysics · Physics 2008-02-21 S. P. Rajaguru

The detection of Earth-like planets with the radial-velocity method is currently limited by the presence of stellar activity signatures. On rotational timescales, spots and plages (or faculae) are known to introduce different RV signals,…

Solar and Stellar Astrophysics · Physics 2023-10-25 M. Cretignier , A. G. M. Pietrow , S. Aigrain

In the present work we show robust indications of the existence of g modes in the Sun using 10 years of GOLF data. The present analysis is based on the exploitation of the collective properties of the predicted low-frequency (25 to 140…

We present statistical analysis of 11,200 proton kinetic-scale current sheets (CS) observed by Parker Solar Probe during 10 days around the first perihelion. The CS thickness $\lambda$ is in the range from a few to 200 km with the typical…

Solar and Stellar Astrophysics · Physics 2022-04-20 A. Lotekar , I. Y. Vasko , T. Phan , S. D. Bale , T. A. Bowen , J. Halekas , A. V. Artemyev , Yu. Khotyaintsev , F. S. Mozer

In this Letter we present a seismological detection of a rising motion of magnetic flux in the shallow convection zone of the Sun, and show estimates of the emerging speed and its decelerating nature. In order to evaluate the speed of…

Solar and Stellar Astrophysics · Physics 2015-06-15 Shin Toriumi , Stathis Ilonidis , Takashi Sekii , Takaaki Yokoyama

We use high spatial resolution observations and numerical simulations to study the velocity distribution of solar photospheric magnetic bright points. The observations were obtained with the Rapid Oscillations in the Solar Atmosphere…

The Sun is replete with magnetic fields, with sunspots, pores and plage regions being their most prominent representatives on the solar surface. But even far away from these active regions, magnetic fields are ubiquitous. To a large extent,…

Solar and Stellar Astrophysics · Physics 2015-11-05 Andreas Lagg , Bruce Lites , Jack Harvey , Sanjay Gosain , Rebecca Centeno

The Ca-K spectroheliograms obtained at the Kodaikanal observatory (KO) are used to generate a uniform time series using the equal contrast technique (ECT) to study the long and short-term variation in the solar chromosphere. The percentage…

Solar and Stellar Astrophysics · Physics 2023-03-08 Muthu Priyal , Jagdev Singh , Belur Ravindra , G. Sindhuja

We study the formation of a sunspot penumbra in the active region NOAA11024. We simultaneously observed the Stokes parameters of the photospheric iron lines at 1089.6 nm with the TIP and 617.3 nm with the GFPI spectropolarimeters along with…

Solar and Stellar Astrophysics · Physics 2011-11-15 Reza Rezaei , Nazaret Bello Gonzalez , Rolf Schlichenmaier

Bright points (BPs) are manifestations of small magnetic elements in the solar photosphere. Their brightness contrast not only gives insight into the thermal state of the photosphere (and chromosphere) in magnetic elements, but also plays…

On the basis of observations of solar granulation obtained with the New Solar Telescope (NST) of Big Bear Solar Observatory, we explored proper motion of bright points (BPs) in a quiet sun area, a coronal hole, and an active region plage.…

Solar and Stellar Astrophysics · Physics 2011-11-21 V. I. Abramenko , V. Carbone , V. Yurchyshyn , P. R. Goode , R. F. Stein , F. Lepreti , V. Capparelli , A. Vecchio

Recent high resolution spectropolarimetric observations from Hinode detected the presence of supersonic downflows in a sunspot light bridge (Louis et al. 2009). These downflows occurred in localized patches, close to regions where the field…

Solar and Stellar Astrophysics · Physics 2012-06-21 Rohan E. Louis , Luis R. Bellot Rubio , Shibu K. Mathew , P. Venkatakrishnan