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Related papers: Heating by Acoustic Waves of Multiphase Media

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Slow magnetoacoustic waves (SMAWs) have been considered in the past as a possible candidate for chromospheric heating. This study analyzes 20 active regions observed between 2012 and 2016 to examine the amplitude and energy flux variation…

Solar and Stellar Astrophysics · Physics 2025-04-22 Y. Sanjay , S. Krishna Prasad , P. S. Rawat

We consider the stability of clouds surrounded by a hotter confining medium with respect to which they are in motion, against Kelvin-Helmholtz instabilities (KHI). In the presence of cooling, sound waves are damped by dissipation. Whenever…

Astrophysics · Physics 2009-10-30 Mario Vietri , Andrea Ferrara , Francesco Miniati

Propagation of acoustic waves in an one-dimensional water duct containing many air filled blocks is studied by the transfer matrix formalism. Energy distribution and interface vibration of the air blocks are computed. For periodic…

Condensed Matter · Physics 2009-10-31 Pi-Gang Luan , Zhen Ye

We study experimentally the dissipative dynamics of ultracold bosonic gases in a dynamic disorder potential with tunable correlation time. First, we measure the heating rate of thermal clouds exposed to the dynamic potential and present a…

An enhancement in high-frequency acoustic power is commonly observed in the solar photosphere and chromosphere surrounding magnetic active regions. We perform 3D linear forward wave modelling with a simple wavelet pulse acoustic source to…

Solar and Stellar Astrophysics · Physics 2015-06-23 Carlos Rijs , Hamed Moradi , Damien Przybylski , Paul S. Cally

We investigate sound wave propagation in a monatomic gas using a volume-based hydrodynamic model. In Physica A vol 387(24) (2008) pp6079-6094, a microscopic volume-based kinetic approach was proposed by analyzing molecular spatial…

Fluid Dynamics · Physics 2009-07-31 S. Kokou Dadzie , Jason M. Reese

Continuum observations at radio, millimetre, infrared and soft X-ray energies are presented for a sample of 22 quasars, consisting of flat and steep spectrum radio loud, radio intermediate and radio quiet objects. The primary observational…

Astrophysics · Physics 2007-05-23 M. Polletta , T. J. -L. Courvoisier , E. J. Hooper , B. J. Wilkes

An effect we have termed the acousto-thermoelectric effect is theorized for temperature gradients driven by acoustic modulation. The effect produces a dynamic and spatially varying voltage. Adiabatic acoustic fluctuations in a solid cause…

Applied Physics · Physics 2023-03-24 Hasan Salehi Najafabadi , Mark. A. Meier , Gary A. Hallock

We have calculated the radiation field, dust grain temperatures, and far infrared emissivity of numerical models of turbulent molecular clouds. When compared to a uniform cloud of the same mean optical depth, most of the volume inside the…

Astrophysics · Physics 2009-11-10 Thomas Bethell , Ellen Zweibel , Fabian Heitsch , J. S. Mathis

The well-observed acoustic halo is an enhancement in time-averaged Doppler velocity and intensity power with respect to quiet-sun values which is prominent for weak and highly inclined field around the penumbra of sunspots and active…

Solar and Stellar Astrophysics · Physics 2016-01-27 Carlos Rijs , S. P. Rajaguru , Damien Przybylski , Hamed Moradi , Paul S. Cally , Sergiy Shelyag

The hot plasma permeating clusters of galaxies often shows a central peak in the X-ray surface brightness that is coincident with a drop in entropy. This is taken as evidence for a cooling flow where the radiative cooling in the central…

Astrophysics · Physics 2015-06-24 Marcus Brueggen , Christian R. Kaiser

We examine heating and cooling in protostellar disks using 3-D radiation-MHD calculations of a patch of the Solar nebula at 1 AU, employing the shearing-box and flux-limited radiation diffusion approximations. The disk atmosphere is ionized…

Earth and Planetary Astrophysics · Physics 2015-05-27 S. Hirose , N. J. Turner

This paper shows that magnetic reconnection could be an important heating process in cosmic gases. In any volume where magnetized plasmas collide, the dissipation of magnetic energy via reconnection seems to be unavoidable. Since most…

Astrophysics · Physics 2007-05-23 F. Zimmer , H. Lesch , G. T. Birk

The impact of thermodiffusive effects on combustion noise in turbulent premixed slot jet flames is investigated using Direct Numerical Simulations. Two thermodiffusively unstable lean hydrogen-air flames are compared with a…

Fluid Dynamics · Physics 2026-03-20 Francesco G. Schiavone , Guillaume Daviller , Davide Laera

We have performed 3D radiation MHD simulations extending from the convection zone to the corona covering a box 16 Mm$^3$ at 32 km spatial resolution. The simulations show very fine structure in the chromosphere with acoustic shocks…

Solar and Stellar Astrophysics · Physics 2010-01-12 Mats Carlsson , Viggo H. Hansteen , Boris V. Gudiksen

We present an investigation on effect of the ion-neutral (or ambipolar) diffusion heating rate on thermal phases of a molecular cloud. We use the modeling of ambipolar diffusion with two-fluid smoothed particle hydrodynamics, as discussed…

Astrophysics · Physics 2008-04-29 M. Nejad-Asghar , D. Molteni

Acoustically driven mixing of small fluid volumes is reported. Using surface acoustic waves on a mixer chip, conversion of those into bulk waves, and employing wave guiding effects enables us to distribute a set of "virtual sources" for…

Fluid Dynamics · Physics 2007-05-23 Andreas Rathgeber , Matthias Wassermeier , Achim Wixforth

In conventional models of galactic and cluster cooling flows widespread cooling (mass dropout) is assumed to avoid accumulation of unacceptably large central masses. However, recent XMM observations have failed to find spectral evidence for…

Astrophysics · Physics 2009-11-07 Fabrizio Brighenti , William G. Mathews

Context. Multitransition CO observations of galaxy centers have revealed that significant fractions of the dense circumnuclear gas have high kinetic temperatures, which are hard to explain by pure photon excitation, but may be caused by…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 M. V. Kazandjian , R. Meijerink , I. Pelupessy , F. P. Israel , M. Spaans

Cold clouds embedded in warm media are very common objects in astrophysics. Their disruption timescale depends strongly on the dynamical configuration. We discuss the evolution of an initially homogeneous cold cloud embedded in warm…

Astrophysics · Physics 2009-11-11 F. Heitsch , A. D. Slyz , J. E. G. Devriendt , A. Burkert
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