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Zonal jets manifest themselves as bands with sharp interfaces in the vorticity configuration. We develop an algorithm to track these fluctuating vorticity interfaces and systematically investigate their characteristic spatio-temporal…

Fluid Dynamics · Physics 2025-08-01 Sandip Sahoo , Samriddhi Sankar Ray

We report the discovery and characterization of high-speed (>100 km/s) horizontal flows in solar active regions, making use of the Sun-as-a-star spectroscopy in the range 5-105 nm provided by the EVE (Extreme Ultraviolet Variability…

We report on the detection with RXTE of variable high frequency features in the power spectra of the black hole candidate 4U 1630-47 during its 1998 outburst. We find high frequency features during the rise and the early decay of the…

Astrophysics · Physics 2009-11-10 Marc Klein-Wolt , Jeroen Homan , Michiel van der Klis

The center-to-limb variations (CLVs) of photospheric and chromospheric spectral lines were obtained in 2025 July and August using drift scans from the echelle spectrograph of the 0.7 m Vacuum Tower Telescope at the Observatorio del Teide…

Solar and Stellar Astrophysics · Physics 2025-11-10 Meetu Verma , Carsten Denker , Alexander G. M. Pietrow , Robert Kamlah , Dominique J. M. Petit dit de la Roche

Due to the non-linearity of Hertzian contacts, the speed of sound $c$ in granular matter is expected to increase with pressure as $P^{1/6}$. A static layer of grains under gravity is thus stratified so that bulk waves are refracted toward…

Soft Condensed Matter · Physics 2007-05-23 L. Bonneau , B. Andreotti , E. Clement

High spatial and temporal resolution images of a sunspot, obtained simultaneously in multiple optical and UV wavelengths, are employed to study the propagation and damping characteristics of slow magnetoacoustic waves up to transition…

Solar and Stellar Astrophysics · Physics 2017-09-20 S. Krishna Prasad , D. B. Jess , T. Van Doorsselaere , G. Verth , R. J. Morton , V. Fedun , R. Erdelyi , D. J. Christian

Densely time sampled multi-frequency flux measurements of the extreme BL Lac object S5 0716+714 over the past three years allow us to study its broad-band variability, and the detailed underlying physics, with emphasis on the location and…

High Energy Astrophysical Phenomena · Physics 2019-08-16 B. Rani , T. P. Krichbaum , L. Fuhrmann , B. Lott , M. Boettcher , J. A. Zensus

Level and wavefunction statistics have been studied for two dimensional clusters of the square lattice in the presence of random magnetic fluxes. Fluxes traversing lattice plaquettes are distributed uniformly between - (1/2) Phi_0 and (1/2)…

Condensed Matter · Physics 2009-10-28 J. A. Verges

We study the possibility for the implementation of linear wave structures on discrete grids with various dimensions. The systems of the first order differential equations for the set of virtual functions, describing the wave propagation,…

Numerical Analysis · Mathematics 2019-01-01 Sergey Dvornikov , Maxim Dvornikov

In this paper I report on the recent results obtained from the Tenerife switched beam (10 GHz to 33 GHz) experiment and Jodrell Bank 5 GHz interferometer and their predictions for foreground levels. The full data analysis and results will…

Astrophysics · Physics 2007-05-23 A. W. Jones

A spectrogram is a useful way of using short-time discrete Fourier transforms to visualise surface height measurements taken of ship wakes in real world conditions. For a steadily moving ship that leaves behind small-amplitude waves, the…

Fluid Dynamics · Physics 2016-12-21 Ravindra Pethiyagoda , Scott W. McCue , Timothy J. Moroney

We investigate the statistics of the intensity distributions as function of the wavelength for Ca II H and the CA II IR line at 854.2 nm to estimate the energy content. We derived the intensity variations at different heights of the solar…

Solar and Stellar Astrophysics · Physics 2013-03-14 C. Beck , R. Rezaei , K. G. Puschmann

Propagating perturbations have been observed in extended coronal loop structures for a number of years, but the interpretation in terms of slow (propagating) magneto-acoustic waves and/or as quasi-periodic upflows remains unresolved. We…

Solar and Stellar Astrophysics · Physics 2015-10-06 Ineke De Moortel , Patrick Antolin , Tom Van Doorsselaere

There is a growing interest in exploiting the terahertz frequency band for future communication systems that demand high data rates. Given the complex propagation behavior of this frequency band, various researchers have developed channel…

Signal Processing · Electrical Eng. & Systems 2022-10-17 Ha Tran , Thanh Le , Suresh Singh

Recent discoveries of highly dispersed millisecond radio bursts by Thornton et al. in a survey with the Parkes radio telescope at 1.4 GHz point towards an emerging population of sources at cosmological distances whose origin is currently…

High Energy Astrophysical Phenomena · Physics 2015-06-16 D. R. Lorimer , A. Karastergiou , M. A. McLaughlin , S. Johnston

FR3 ($\approx$7-24 GHz), also referred to as the upper mid-band, has recently emerged as promising spectrum for 6G; however, its propagation and MIMO characteristics vary significantly with frequency and environment, and spectrum…

Information Theory · Computer Science 2026-01-13 Emiel Vanspranghels , Zhuangzhuang Cui , Sofie Pollin

We investigate the small scale equidistribution properties of random waves in $\mathbb{R}^{n}$. Numerical evidence suggests that such objects display a fine scale filament structure. We show that the X-ray along any line segment is…

Analysis of PDEs · Mathematics 2023-01-10 Melissa Tacy

We report hot-wire measurements performed in two very different, co- and counter-rotating flows, in normal and superfluid helium at 1.6 K, 2 K, and 2.3 K. As recently reported, the power spectrum of the hot-wire signal in superfluid flows…

We have mapped the powerful radio galaxy Hercules A at six frequencies spanning 1295 to 8440 MHz using the VLA in all four configurations. Here we discuss the structure revealed in total intensity, spectral index, polarization, and…

Astrophysics · Physics 2009-11-07 Nectaria A. B. Gizani , J. P. Leahy

This paper investigates the effect of oscillator phase noise and channel variations due to fading on the performance of communication systems at frequency bands higher than 10GHz. Phase noise and channel models are reviewed and…

Information Theory · Computer Science 2016-11-18 M. Reza Khanzadi , Rajet Krishnan , Dan Kuylenstierna , Thomas Eriksson