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Phase-mixing of Alfv\'en waves in the solar corona has been identified as one possible candidate to explain coronal heating. While this scenario is supported by observations of ubiquitous oscillations in the corona carrying sufficient wave…

Solar and Stellar Astrophysics · Physics 2017-05-17 Paolo Pagano , Ineke De Moortel

The solar atmosphere may be heated by Alfven waves that propagate up from the convection zone and dissipate their energy in the chromosphere and corona. To further test this theory, we consider wave heating in an active region observed on…

Solar and Stellar Astrophysics · Physics 2015-06-16 M. Asgari-Targhi , A. A. van Ballegooijen , S. R. Cranmer , E. E. DeLuca

Interaction of Alfven waves with plasma inhomogeneities generates phase mixing which can lead to dissipate Alfven waves and to heat the solar plasma. Here we study the dissipation of Alfven waves by phase mixing due to viscosity and…

Solar and Stellar Astrophysics · Physics 2015-06-18 Z. Fazel , H. Ebadi

Using high resolution cosmological simulations, we study hydrogen and helium gravitational cooling radiation. We focus on the HeII cooling lines, which arise from gas with a different temperature history (T_max ~ 10^5K) than HI line…

With first-principles kinetic simulations, we show that a large-scale Alfv\'en wave (AW) propagating in an inhomogeneous background decays into kinetic Alfv\'en waves (KAWs), triggering ion and electron energization. We demonstrate that the…

Plasma Physics · Physics 2022-04-27 Fabio Bacchini , Francesco Pucci , Francesco Malara , Giovanni Lapenta

Context: This paper investigates the effectiveness of phase mixing as a coronal heating mechanism. A key quantity is the wave damping rate, $\gamma$, defined as the ratio of the heating rate to the wave energy. Aims: We investigate whether…

Solar and Stellar Astrophysics · Physics 2019-12-11 A. P. K. Prokopyszyn , A. W. Hood

The Alfven wave is analyzed in case of one quasineutral plasma propagating with some constant speed $v_0$ through another static quasineutral plasma. A dispersion equation is derived describing the Alfven wave coupled with the flow driven…

Plasma Physics · Physics 2015-10-20 J. Vranjes

Particle heating in advection-dominated accretion flows (ADAFs) by nonlinear MHD (Alfvenic) turbulence is investigated. Such turbulence with highly-fluctuating magnetic fields, $\tilde B\sim B_0$, is believed to be naturally produced by the…

Astrophysics · Physics 2015-06-24 Mikhail V. Medvedev

In this paper we further develop a model for the heating of coronal loops by Alfven wave turbulence (AWT). The Alfven waves are assumed to be launched from a collection of kilogauss flux tubes in the photosphere at the two ends of the loop.…

Solar and Stellar Astrophysics · Physics 2017-11-08 Adriaan A. van Ballegooijen , Mahboubeh Asgari-Targhi , Alexander Voss

Alfven waves have been invoked as an important mechanism of particle acceleration in stellar winds of cool stars. After their identification in the solar wind they started to be studied in winds of stars located in different regions of the…

Solar and Stellar Astrophysics · Physics 2014-11-18 A. A. Vidotto , V. Jatenco-Pereira

We study the propagation, reflection, and turbulent dissipation of Alfven waves in coronal holes and the solar wind. We start with the Heinemann-Olbert equations, which describe non-compressive magnetohydrodynamic fluctuations in an…

Solar and Stellar Astrophysics · Physics 2014-11-20 Benjamin D. G. Chandran , Joseph V. Hollweg

The Alfv\'en wave energy flux in the corona can be explored using the electron density and velocity amplitude of the waves. The velocity amplitude of Alfv\'en waves can be obtained from the non-thermal velocity of the spectral line…

Solar and Stellar Astrophysics · Physics 2019-07-03 Girjesh R. Gupta , G. Del Zanna , H. E. Mason

We show that a helical shear flow of a magnetized plasma may serve as an efficient amplifier of Alfven waves. We find that even when the flow is purely ejectional (i.e., when no rotation is present) Alfven waves are amplified through the…

Astrophysics · Physics 2009-11-07 Andria D. Rogava , Swadesh M. Mahajan , Gianluigi Bodo , Silvano Massaglia

Observations have shown that magnetohydrodynamic waves over a large frequency range are ubiquitous in solar prominences. The waves are probably driven by photospheric motions and may transport energy up to prominences suspended in the…

Solar and Stellar Astrophysics · Physics 2016-07-13 Roberto Soler , Jaume Terradas , Ramon Oliver , Jose Luis Ballester

This work is an extension of Kaghashvili [1999] where ion-cyclotron wave dissipation channel for Alfv\'en waves was discussed. While our earlier study dealt with the mode coupling in the commonly discussed sense, here we study changes in…

Solar and Stellar Astrophysics · Physics 2014-02-10 Edisher Kh. Kaghashvili

The AlF molecule, currently subject to laser cooling and trapping efforts, has the advantage that it can be efficiently produced in a thermochemical reaction between sublimated aluminum trifluoride and aluminum metal. Here we present a…

A growing body of evidence suggests that the solar wind is powered to a large extent by an Alfv\'en-wave (AW) energy flux. AWs energize the solar wind via two mechanisms: heating and work. We use high-resolution direct numerical simulations…

Solar and Stellar Astrophysics · Physics 2021-05-05 Jean C. Perez , Benjamin D. G. Chandran , Kristopher G. Klein , Mihailo M. Martinović

The standard cooling flow model has predicted a large amount of cool gas in the clusters of galaxies. The failure of the Chandra and XXM-Newton telescopes to detect cooling gas (below 1-2 keV) in clusters of galaxies has suggested that some…

Astrophysics · Physics 2007-10-13 Nasser Mohamed Ahmed

We investigate off-limb active region and quiet Sun corona using spectroscopic data. Active region is clearly visible in several spectral lines formed in the temperature range of 1.1--2.8 MK. We derive electron number density using line…

Solar and Stellar Astrophysics · Physics 2017-02-07 G. R. Gupta

Recent studies have shown that galaxies accrete most of their baryons via the cold mode, from streams with temperatures T~10^4-10^5 K. At these temperatures, the streams should radiate primarily in the Lya line and have therefore been…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 C. -A. Faucher-Giguere , D. Keres , M. Dijkstra , L. Hernquist , M. Zaldarriaga