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We characterize the observational properties of the convectively driven vortex flows recently discovered on the quiet Sun, using magnetograms, Dopplergrams and images obtained with the 1-m balloon-borne Sunrise telescope. By visual…

We have measured the energy and dissipation of Alfvenic waves in the quiet Sun. A magnetic field was used to infer the location and orientation of the magnetic field lines along which the waves are expected to travel. The waves were…

Solar and Stellar Astrophysics · Physics 2015-06-22 Michael Hahn , Daniel Wolf Savin

Whistler waves are present in solar wind plasma. These waves possess characteristic turbulent fluctuations that are characterized typically by the frequency and length scales that are respectively bigger than ion gyro frequency and smaller…

Space Physics · Physics 2015-05-14 Dastgeer Shaikh , G. P. Zank

We review (i) observations and numerical simulations of vortical flows in the solar atmosphere and (ii) measurements of the horizontal magnetic field in quiet Sun regions. First, we discuss various manifestations of vortical flows and…

Solar and Stellar Astrophysics · Physics 2012-02-21 O. Steiner , R. Rezaei

We investigate the properties and relationship between Doppler-velocity fluctuations and intensity fluctuations in the off-limb quiet Sun corona. These are expected to reflect the properties of Alfvenic and compressive waves, respectively.…

Solar and Stellar Astrophysics · Physics 2025-03-21 Michael Hahn , Xiangrong Fu , Stefan J. Hofmeister , Yifan Huang , Alexandros Koukras , Daniel Wolf Savin

The first two orbits of the Parker Solar Probe (PSP) spacecraft have enabled the first in situ measurements of the solar wind down to a heliocentric distance of 0.17 au (or 36 Rs). Here, we present an analysis of this data to study solar…

We present high-resolution observations of two kinds of dynamic behavior in a quiescent prominence using the New Vacuum Solar Telescope, i.e., Kelvin-Helmholtz instabilities (KHIs) and small-scale oscillations. The KHIs were identified as…

Solar and Stellar Astrophysics · Physics 2018-08-29 Dong Li , Yuandeng Shen , Zongjun Ning , Qingmin Zhang , Tuanhui Zhou

High-resolution observations of a quiet Sun internetwork region taken with the Solar 1-m Swedish Telescope in La Palma are analyzed. We determine the location of small-scale vortex motions in the solar photospheric region by computing the…

Solar and Stellar Astrophysics · Physics 2015-05-28 S. Vargas Dominguez , J. Palacios , L. Balmaceda , I. Cabello , V. Domingo

A simple model of a periodic ensemble of closely packed flux tubes sitting atop a vertically stratified layer reveals that an incident fast wave from below preferentially converts almost immediately to Alfv\'en waves in the flux tubes, with…

Solar and Stellar Astrophysics · Physics 2017-01-18 Paul S. Cally

Measurements of oscillation frequencies of the Sun and stars can provide important independent constraints on their internal structure and dynamics. Seismic models of these oscillations are used to connect structure and rotation of the star…

Solar and Stellar Astrophysics · Physics 2015-05-18 Jishnu Bhattacharya , Shravan. M. Hanasoge , H. M. Antia

We investigate vortex dynamics in three magnetic regions, viz., Quiet Sun, Weak Plage, and Strong Plage, using realistic three-dimensional simulations from a comprehensive radiation-MHD code, MURaM. We find that the spatial extents and…

Solar and Stellar Astrophysics · Physics 2024-08-16 Arjun Kannan , Nitin Yadav

This Letter presents a calculation of the power spectra of weakly turbulent Alfven waves and fast magnetosonic waves ("fast waves") in low-beta plasmas. It is shown that three-wave interactions transfer energy to high-frequency fast waves…

Astrophysics · Physics 2009-11-11 Benjamin D. G. Chandran

Metrewave solar type-III radio bursts offer a unique means to study the properties of turbulence across the coronal heights.Theoretical models have shown that the apparent intensity and size of the burst sources evolve at sub-second scales…

Solar and Stellar Astrophysics · Physics 2021-11-24 Atul Mohan

Linear properties of kinetic Alfv\'{e}n waves (KAWs) and kinetic slow waves (KSWs) are studied in the framework of two-fluid magnetohydrodynamics. We obtain the wave dispersion relations that are valid in a wide range of the wave frequency…

Solar and Stellar Astrophysics · Physics 2014-09-16 J. S. Zhao , Y. Voitenko , M. Y. Yu , J. Y. Lu , D. J Wu

At the site of their origin, solar meterwave radio bursts contain pristine information about the local coronal magnetic field and plasma parameters. On its way through the turbulent corona, this radiation gets substantially modified due to…

Solar and Stellar Astrophysics · Physics 2019-05-01 Atul Mohan , Surajit Mondal , Divya Oberoi , Colin Lonsdale

The solar atmosphere is known to be replete with magneto-hydrodynamic wave modes, and there has been significant investment in understanding how these waves propagate through the Sun's atmopshere and deposit their energy into the plasma.…

Solar and Stellar Astrophysics · Physics 2023-02-14 R. J. Morton , R. Sharma , E. Tajfirouze , H. Miriyala

One proposed mechanism for heating the solar wind, from close to the sun to beyond 10 AU, invokes low-frequency, oblique, Alfven-wave turbulence. Because small-scale oblique Alfven waves (kinetic Alfven waves) are compressive, the measured…

Solar and Stellar Astrophysics · Physics 2015-05-13 Benjamin D. G. Chandran , Eliot Quataert , Gregory G. Howes , Qian Xia , Peera Pongkitiwanichakul

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

Small-scale magnetic field concentrations (magnetic elements) in the quiet Sun are believed to contribute to the energy budget of the upper layers of the Sun's atmosphere, as they are observed to support a large number of MHD modes. In…

Solar and Stellar Astrophysics · Physics 2015-04-29 M. Stangalini , F. Giannattasio , S. Jafarzadeh

Alfv\'enic fluctuations are very common features in the solar wind and are found especially within the main portion of fast wind streams while the slow wind usually is less Alfv\'enic and more variable. In general, fast and slow wind show…

Space Physics · Physics 2018-12-19 Raffaella D'Amicis , Lorenzo Matteini , Roberto Bruno