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Context. The spatial power spectrum of supergranulation does not fully characterize the underlying physics of turbulent convection. For example, it does not describe the non-Gaussianity in the horizontal flow divergence. Aims. Our aim is to…

Solar and Stellar Astrophysics · Physics 2020-04-01 Vincent G. A. Böning , Aaron C. Birch , Laurent Gizon , Thomas L. Duvall , Jesper Schou

Context. The height structure of 3-min oscillations over sunspots is studied in the context of the recently discovered effect of height inversion: over the umbra, the spatial location of the maximum of chromospheric 3-min oscillation power…

Solar and Stellar Astrophysics · Physics 2013-02-11 N. I. Kobanov , D. Y. Kolobov , S. A. Chupin , V. M. Nakariakov

We present a study of wave processes occurring in solar active region NOAA 11131 on 2010 December 10, captured by the Solar Dynamics Observatory in the 1600A, 304A, and 171A channels. For spectral analysis we employed pixelised wavelet…

Solar and Stellar Astrophysics · Physics 2021-01-20 Robert Sych , David B. Jess , Jiangtao Su

Slow magnetoacoustic waves are omnipresent in both natural and laboratory plasma systems. The wave-induced misbalance between plasma cooling and heating processes causes the amplification or attenuation, and also dispersion, of slow…

Solar and Stellar Astrophysics · Physics 2020-01-29 D. I. Zavershinskii , D. Y. Kolotkov , V. M. Nakariakov , N. E. Molevich , D. S. Ryashchikov

We investigate the transition of the solar wind turbulent cascade from MHD to sub-ion range by means of a detail comparison between in situ observations and hybrid numerical simulations. In particular we focus on the properties of the…

Space Physics · Physics 2020-09-01 L. Matteini , L. Franci , O. Alexandrova , C. Lacombe , S. Landi , P. Hellinger , E. Papini , A. Verdini

The dynamics of regions of the solar corona are investigated using Atmospheric Imaging Assembly (AIA) 171\AA\ and 193\AA\ data. The coronal emission from the quiet Sun, coronal loop footprints, coronal moss, and from above a sunspot is…

Solar and Stellar Astrophysics · Physics 2015-06-23 Jack Ireland , R. T. James McAteer , Andrew R. Inglis

Magnetohydrodynamic (MHD) turbulence in the solar wind is observed to show the spectral behavior of classical Kolmogorov fluid turbulence over an inertial subrange and departures from this at short wavelengths, where energy should be…

Space Physics · Physics 2009-11-11 S. D. Bale , P. J. Kellogg , F. S. Mozer , T. S. Horbury , H. Reme

Five-minute oscillations on the Sun (acoustic and surface gravity waves) are excited by subsurface turbulent convection. However, in sunspots the excitation is suppressed because strong magnetic field inhibits convection. We use 3D…

Astrophysics · Physics 2009-11-13 K. V. Parchevsky , A. G. Kosovichev

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

Solar oscillation frequencies change with the level of magnetic activity. Localizing subsurface magnetic field concentrations in the Sun with helioseismology will help us to understand the solar dynamo. Because the magnetic fields are not…

Solar and Stellar Astrophysics · Physics 2018-02-28 René Kiefer , Markus Roth

We analyzed intermittency in the solar wind, as observed on the ecliptic plane, looking at magnetic field and velocity fluctuations between 0.3 and 1 AU, for both fast and slow wind and for compressive and directional fluctuations. Our…

Astrophysics · Physics 2015-06-24 R. Bruno , V. Carbone , L. Sorriso-Valvo , B. Bavassano

The frequencies of Shubnikov-de Haas oscillations have long been used to measure the unequal population of spin-split two-dimensional subbands in inversion asymmetric systems. We report self-consistent numerical calculations and…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 R. Winkler , S. J. Papadakis , E. P. De Poortere , M. Shayegan

Frequency splitting coefficients from Global Oscillation Network Group (GONG) and Michelson Doppler Imager (MDI) observations covering the period 1995--2001 are used to study temporal variations in the solar rotation rate at high latitudes.…

Astrophysics · Physics 2009-11-07 H. M. Antia , Sarbani Basu

Using the Parker Solar Probe data taken in the inner heliosphere, we investigate the power and spatial anisotropy of magnetic-field spectra at kinetic scales (i.e., around sub-ion scales) in solar wind turbulence in the inner heliosphere.…

Solar and Stellar Astrophysics · Physics 2022-04-20 S. Y. Huang , S. B. Xu , J. Zhang , F. Sahraoui , N. Andres , J. S. He , Z. G. Yuan , X. H. Deng , K. Jiang , Y. Y. Wei , Q. Y. Xiong , Z. Wang , L. Yu , R. T. Lin

We describe a technique for probing the statistical properties of cosmic magnetic fields based on radio polarimetry data. Second-order magnetic field statistics like the power spectrum cannot always distinguish between magnetic fields with…

Astrophysics of Galaxies · Physics 2015-05-13 A. Waelkens , A. A. Schekochihin , T. A. Ensslin

Measurements of seismic wave travel times at the photosphere of the Sun have enabled inferences of its interior structure and dynamics. In interpreting these measurements, the simplifying assumption that waves propagate through a temporally…

Earth and Planetary Astrophysics · Physics 2015-06-16 Shravan Hanasoge , Laurent Gizon , Guillaume Bal

The power spectrum of the evolving solar wind shows evidence of a spectral break between an inertial range of turbulent fluctuations at higher frequencies and a "$1/f$" like region at lower frequencies. In the ecliptic plane at $\sim 1$ AU,…

Solar and Stellar Astrophysics · Physics 2009-09-24 R. M. Nicol , S. C. Chapman , R. O. Dendy

Synchronization in neural system plays an important role in many brain functions. Synchronization in the gamma frequency band (30Hz-100Hz) is involved in a variety of cognitive phenomena; abnormalities of the gamma synchronization are found…

Neurons and Cognition · Quantitative Biology 2021-04-26 Quynh-Anh Nguyen , Leonid L Rubchinsky

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

Two sequences of solar images obtained by the Transition Region and Coronal Explorer in three UV passbands are studied using wavelet and Fourier analysis and compared to the photospheric magnetic flux measured by the Michelson Doppler…