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We explore the sensitivity of the frequencies of low-degree solar p-modes to near-surface magnetic flux on different spatial scales and strengths, specifically to active regions with strong magnetic fields and ephemeral regions with weak…

We study the magnetic excitation spectrum in three-dimensional diluted ferromagnetic nearest-neighbor systems down to the percolation threshold. The disorder effects resulting from the dilution are handled accurately within self-consistent…

Strongly Correlated Electrons · Physics 2010-05-19 Akash Chakraborty , Georges Bouzerar

Solar chromospheric observations of sunspot umbrae offer an exceptional view of magneto-hydrodynamic wave phenomena. In recent years, a wealth of wave signatures related to propagating magneto-acoustic modes have been presented, which…

We have developed 3D, compressible, non-linear radiative MHD simulations to study the influence of the magnetic field of various strength and geometry on the turbulent convective cells and on the excitation mechanisms of the acoustic…

Solar and Stellar Astrophysics · Physics 2009-01-29 Irina Kitiashvili , Laetitia Jacoutot , Alexander Kosovichev , Alan Wray , Nagi Mansour

Atmospheric water vapor causes significant undesired phase fluctuations for the Submillimeter Array (SMA) interferometer, particularly in its highest frequency observing band of 690 GHz. One proposed solution to this atmospheric effect is…

Astrophysics · Physics 2007-05-23 D. Y. Kubo , T. R. Hunter , R. D. Christensen , P. I. Yamaguchi

We study the time-evolution of axisymmetric oscillations of superfluid magnetars with a poloidal magnetic field and an elastic crust, working in Newtonian gravity. Extending earlier models, we study the effects of composition gradients and…

Solar and Stellar Astrophysics · Physics 2015-06-16 A. Passamonti , S. K. Lander

We consider a slow-fast Hamiltonian system with one fast angular variable (a fast phase) whose frequency vanishes on some surface in the space of slow variables (a resonant surface). Systems of such form appear in the study of dynamics of…

Dynamical Systems · Mathematics 2022-12-29 Yuyang Gao , Anatoly Neishtadt , Alexey Okunev

The interaction of surface acoustic waves (SAW) with $p$-type Si/Si$_{0.87}$Ge$_{0.13}$ heterostructures has been studied for SAW frequencies of 30-300 MHz. For temperatures in the range 0.7$<T<$1.6 K and magnetic fields up to 7 T, the SAW…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 I. L. Drichko , A. M. Diakonov , I. Yu. Smirnov , G. O. Andrianov , O. A. Mironov , M. Myronov , D. R. Leadley , T. E. Whall

Using high-resolution ring analysis (HRRA) we deduce subsurface flows within magnetic active regions and within quiet sun. With this procedure we are capable of measuring flows with a horizontal spatial resolution of 2 degrees in…

Solar and Stellar Astrophysics · Physics 2011-02-11 Bradley W. Hindman , Deborah A. Haber , Juri Toomre

We investigate the spatial and temporal variations of the high-degree mode frequencies calculated over localized regions of the Sun during the extended minimum phase between solar cycles 23 and 24. The frequency shifts measured relative to…

Solar and Stellar Astrophysics · Physics 2015-06-11 S. C. Tripathy , K. Jain , Frank Hill

Wave propagation in magnetically structured atmospheres is a thoroughly studied, yet practically inexhaustible well of investigations in the field of solar magneto-seismology. A simple but powerful example is the examination of wave…

Solar and Stellar Astrophysics · Physics 2020-04-14 Noémi Kinga Zsámberger , Róbert Erdélyi

In this paper, we first analyze the horizon structure of the acoustic charged black hole in curved spacetime, and then study its acoustic shadow as well as the near-horizon characteristics including the quasinormal modes (QNM) frequencies…

General Relativity and Quantum Cosmology · Physics 2021-11-03 Ru Ling , Hong Guo , Hang Liu , Xiao-Mei Kuang , Bin Wang

We evaluated the body wave attenuation parameter in Kopili region of northeast India. Using the modified algorithm of coda normalization method, we delineated frequency-dependent attenuation for both P and S waves. Taking more than 300…

Geophysics · Physics 2017-07-18 Nilutpal Bora , Rajib Biswas

When exposed to a time-periodic chemical signal, an \textit{E.~coli} cell responds by modulating its receptor activity in a similar time-periodic manner. However, there exists a phase lag between the applied signal and the activity…

Biological Physics · Physics 2025-11-12 Ramesh Pramanik , Ramu K Yadav , Sakuntala Chatterjee

In the approximation of linear dissipative magnetohydrodynamics (MHD) it can be shown that driven MHD waves in magnetic plasmas with high Reynolds number exhibit a near resonant behaviour if the frequency of the wave becomes equal to the…

Astrophysics · Physics 2010-06-18 C. T. M. Clack , I. Ballai , M. S. Ruderman

Inspired by the renewed experimental activities on $p$-wave resonantly interacting atomic Fermi gases, we theoretically investigate some experimental observables of such systems at zero temperature in two dimensions, using both mean-field…

Quantum Gases · Physics 2019-08-21 Hui Hu , Xia-Ji Liu

The Helioseismic and Magnetic Imager (HMI) and the Atmospheric Imaging Assembly (AIA) instruments onboard the Solar Dynamics Observatory satellite produce Doppler velocity and continuum intensity at 6173 A as well as intensity maps at 1600…

Solar and Stellar Astrophysics · Physics 2015-06-17 Sebastien Couvidat

We suggest an explanation for the high-frequency power excess surrounding active regions known as seismic halos. The idea is based on numerical simulations of magneto-acoustic waves propagation in sunspots. We propose that such an excess…

Solar and Stellar Astrophysics · Physics 2015-05-13 E. Khomenko , M. Collados

We present the first observations of large amplitude waves in a well-defined electron diffusion region at the sub-solar magnetopause using data from one THEMIS satellite. These waves identified as whistler mode waves, electrostatic solitary…

Assessment of voice signals has long been performed with the assumption of periodicity as this facilitates analysis. Near periodicity of normal voice signals makes short-time harmonic modeling an appealing choice to extract vocal feature…

Audio and Speech Processing · Electrical Eng. & Systems 2022-02-10 Takeshi Ikuma , Andrew J. McWhorter , Lacey Adkins , Melda Kunduk