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Related papers: Density Fluctuations in the Solar Wind Driven by A…

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We discuss properties of Alfv\'enic fluctuations with large amplitude in plasmas characterised by low magnetic field compression. We note that in such systems power laws can not develop with arbitrarily steep slopes at large scales, i.e.…

Space Physics · Physics 2018-12-26 Lorenzo Matteini , David Stansby , Timothy Horbury , Christopher H. K. Chen

We study the formation and evolution of a turbulent spectrum of Alfv\'en waves driven by reflection off the solar wind density gradients, starting from the coronal base up to 17 solar radii, well beyond the Alfv\'enic critical point. The…

Solar and Stellar Astrophysics · Physics 2009-07-22 A. Verdini , M. Velli , E. Buchlin

Alfv\'en waves are known to be important carriers of magnetic energy that could play a role in coronal heating and/or solar wind acceleration. As these waves are efficient energy carriers, how they are dissipated still remains one of the…

Solar and Stellar Astrophysics · Physics 2025-07-22 Anmol Kumar , Thomas A. Howson , Paolo Pagano , Ineke De Moortel

Using Parker Solar Probe data from orbits 8 through 17, we examine fluctuation amplitudes throughout the critical region where the solar wind flow speed approaches and then exceeds the Alfv\'en wave speed, taking account of various…

The cascade of kinetic Alfv\'en waves (KAWs) at the sub-ion scales in the solar wind is numerically simulated using a fluid approach that retains ion and electron Landau damping, together with ion finite Larmor radius corrections. Assuming…

Solar and Stellar Astrophysics · Physics 2016-02-17 P. L. Sulem , T. Passot , D. Laveder , D. Borgogno

It is well-recognized that the presence of magnetic fields will lead to anisotropic energy cascade and dissipation of astrophysical turbulence. With the diffusion approximation and linear dissipation rates, we study the cascade and damping…

Solar and Stellar Astrophysics · Physics 2009-03-31 Yanwei Jiang , Siming Liu , Vahé Petrosian

The mixture/interaction of anti-sunward-propagating Alfv\'enic fluctuations (AFs) and sunward-propagating Alfv\'enic fluctuations (SAFs) is believed to result in the decrease of the Alfv\'enicity of solar wind fluctuations with increasing…

Space Physics · Physics 2016-06-13 H. Li , C. Wang , J. W. Belcher , J. S. He , J. D. Richardson

We carry out two-dimensional magnetohydrodynamic (MHD) simulations of an ensemble of Alfv\'enic fluctuations propagating in a structured, expanding solar wind including the presence of fast and slow solar wind streams. Using an appropriate…

Solar and Stellar Astrophysics · Physics 2020-01-15 Chen Shi , Marco Velli , Anna Tenerani , Franco Rappazzo , Victor Réville

In magnetized, stratified astrophysical environments such as the Sun's corona and solar wind, Alfv\'enic fluctuations ''reflect'' from background gradients, enabling nonlinear interactions and thus dissipation of their energy into heat.…

Solar and Stellar Astrophysics · Physics 2023-08-22 Romain Meyrand , Jonathan Squire , Alfred Mallet , Benjamin D. G. Chandran

We develop a phenomenological model of strong imbalanced magnetohydrodynamic (MHD) turbulence that accounts for intermittency and the reflection of Alfven waves by spatial variations in the Alfven speed. Our model predicts the slopes of the…

Plasma Physics · Physics 2025-02-10 B. D. G. Chandran , N. Sioulas , S. Bale , T. Bowen , V. David , R. Meyrand , E. Yerger

The anisotropic nature of solar wind magnetic turbulence fluctuations is investigated scale-by-scale using high cadence in-situ magnetic field measurements from the Cluster and ACE spacecraft missions. The data span five decades in scales…

We combine observations of the Coronal Multi-channel Polarimeter (CoMP) and the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) to study the characteristic properties of (propagating) Alfvenic motions and…

Solar and Stellar Astrophysics · Physics 2015-07-02 Jiajia Liu , Scott W. McIntosh , Ineke De Moortel , Yuming Wang

Observations of the solar atmosphere show that internal gravity waves are generated by overshooting convection, but are suppressed at locations of magnetic flux, which is thought to be the result of mode conversion into magneto-acoustic…

Solar and Stellar Astrophysics · Physics 2017-02-01 G. Vigeesh , J. Jackiewicz , O. Steiner

Parametric decay instability (PDI) of Alfv\'en wave is thought to play an important role in the dissipation of the large-amplitude Alfv\'en waves and in the heating of magnetized plasmas. Temperature anisotropy is frequently observed by…

Solar and Stellar Astrophysics · Physics 2026-04-28 Hayato Saguchi , Yohei Kawazura , Munehito Shoda , Yuto Katoh

(Abridged) Turbulence in the solar wind is believed to generate an energy cascade that is supported primarily by Alfv\'en waves or Alfv\'enic fluctuations at MHD scales and by kinetic Alfv\'en waves (KAWs) at kinetic scales $k_\perp…

Solar and Stellar Astrophysics · Physics 2014-11-20 J. J. Podesta , J. E. Borovsky , S. P. Gary

Solar wind is probably the best laboratory to study turbulence in astrophysical plasmas. In addition to the presence of magnetic field, the differences with neutral fluid isotropic turbulence are: weakness of collisional dissipation and…

Solar and Stellar Astrophysics · Physics 2015-06-16 Olga Alexandrova , Christopher H. K. Chen , Luca Sorriso-Valvo , Timothy S. Horbury , Stuart D. Bale

We study the behaviour and properties of the solar wind using a 2.5D Alfv\'en wave driven wind model. We first systematically compare the results of an Alfv\'en wave (AW) driven wind model with a polytropic approach. Polytropic…

Solar and Stellar Astrophysics · Physics 2021-04-14 Soumitra Hazra , Victor Réville , Barbara Perri , Antoine Strugarek , Allan Sacha Brun , Eric Buchlin

Compressive fluctuations are a minor yet significant component of astrophysical plasma turbulence. In the solar wind, long-wavelength compressive slow-mode fluctuations lead to changes in $\beta_{\parallel \mathrm p}\equiv 8\pi n_{\mathrm…

Alfv\'en waves, considered one of the primary candidates for heating and accelerating the fast solar wind, are ubiquitous in spacecraft observations, yet their origin remains elusive. In this study, we analyze data from the first 19…

New aspects of the slow solar wind turbulent heating and acceleration are investigated. A physical meaning of the lower boundary of the Alfv\'en wave turbulent spectra in the solar atmosphere and the solar wind is studied and the…

Solar and Stellar Astrophysics · Physics 2015-06-04 Bidzina M. Shergelashvili , Horst Fichtner