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The solar wind emanates from the hot and tenuous solar corona. Earlier studies using 1.5 dimensional simulations show that Alfv\'{e}n waves generated in the photosphere play an important role in coronal heating through the process of…

Solar and Stellar Astrophysics · Physics 2015-05-30 Takuma Matsumoto , Takeru Ken Suzuki

Alfven waves and ion-cyclotron absorption of high-frequency waves are frequently brought into models devoted to coronal heating and fast solar-wind acceleration. Signatures of ion-cyclotron resonance have already been observed in situ in…

Astrophysics · Physics 2009-11-13 L. Dolla , J. Solomon

Aims. We investigate the transfer of energy between a standing kink mode and azimuthal Alfven waves within an expanding flux tube. We consider the process of resonant absorption in a loop with a non-uniform Alfven frequency profile but in…

Solar and Stellar Astrophysics · Physics 2019-11-06 Thomas Howson , Ineke De Moortel , Patrick Antolin , Tom Van Doorsselaere , Andrew Wright

Small-scale magnetic fields are thought to play an important role in the heating of the outer solar atmosphere. By taking advantage of the unprecedented high-spatial and temporal cadence of IMaX, the filter vector polarimeter on board the…

Solar and Stellar Astrophysics · Physics 2015-06-15 M. Stangalini , S. K. Solanki , R. Cameron , V. Martìnez Pillet

In the context of coronal heating, among the zoo of MHD waves that exist in the solar atmosphere, Alfven waves receive special attention. Indeed, these waves constitute an attractive heating agent due to their ability to carry over the many…

Solar and Stellar Astrophysics · Physics 2014-11-20 P. Antolin , K. Shibata

The efficacy of fast/slow MHD mode conversion in the surface layers of sunspots has been demonstrated over recent years using a number of modelling techniques, including ray theory, perturbation theory, differential eigensystem analysis,…

Astrophysics · Physics 2009-11-13 P. S. Cally , M. Goossens

We present 3D numerical simulations and an analytic model of reflection-driven MHD turbulence in the solar wind. Our simulations describe transverse, non-compressive MHD fluctuations within a narrow magnetic flux tube that extends from the…

Space Physics · Physics 2019-09-04 Benjamin D. G. Chandran , Jean C. Perez

An analytical MHD model of coronal loops with compressible flows and including heating is compared to observational data. The model is constructed via a systematic nonlinear separation of the variables method used to calculate several…

Astrophysics · Physics 2009-11-07 G. J. D. Petrie , C. Gontikakis , H. Dara , K. Tsinganos , M. J. Aschwanden

We investigate the steepening of the magnetic fluctuation power law spectra observed in the inner solar wind for frequencies higher than 0.5 Hz. This high frequency part of the spectrum may be attributed to dispersive nonlinear processes.…

Space Physics · Physics 2009-11-13 S. Galtier

High-frequency wave phenomena present a great deal of interest as one of the possible candidates to contribute to the energy input required to heat the corona as a part of the AC heating theory. However, the resolution of imaging…

Solar and Stellar Astrophysics · Physics 2023-04-05 Elena Petrova , Norbert Magyar , Tom Van Doorsselaere , David Berghmans

The first estimation of the incompressible energy cascade rate at magnetohydrodynamic (MHD) scales is obtained in the plasma upstream of the Martian bow shock, using MAVEN observations and an exact relation derived for MHD turbulence. The…

Magnetohydrodynamic (MHD) waves are ubiquitous in the solar atmosphere. Alfven waves and magneto-sonic waves are particular classes of MHD waves. These wave modes are clearly different and have pure properties in uniform plasmas of infinite…

Solar and Stellar Astrophysics · Physics 2015-06-05 M. Goossens , J. Andries , R. Soler , T. Van Doorsselaere , I. Arregui , J. Terradas

The measured average velocities in solar and stellar spectral lines formed at transition region temperatures have been difficult to interpret. However, realistic three-dimensional radiation magnetohydrodynamics (3D rMHD) models of the solar…

Solar and Stellar Astrophysics · Physics 2018-07-11 P. Zacharias , V. H. Hansteen , J. Leenaarts , M. Carlsson , B. V. Gudiksen

We present direct numerical simulations of inhomogeneous reduced magnetohydrodynamic (RMHD) turbulence between the Sun and the Alfv\'en critical point. These are the first such simulations that take into account the solar-wind outflow…

Solar and Stellar Astrophysics · Physics 2015-06-16 Jean C Perez , Benjamin D. G. Chandran

In the solar atmosphere, Alfv\'en waves are believed to play an important role in the transfer of energy from the photosphere to the corona and solar wind, and in the heating of the chromosphere. We perform numerical computations to…

Solar and Stellar Astrophysics · Physics 2019-01-23 Roberto Soler , Jaume Terradas , Ramon Oliver , Jose Luis Ballester

Recent observations have revealed that MHD waves and oscillations are ubiquitous in the solar atmosphere, with a wide range of periods. We give a brief review of some aspects of MHD waves and coronal seismology which have recently been the…

Solar and Stellar Astrophysics · Physics 2015-06-04 Ineke De Moortel , Valery M. Nakariakov

The thermal fluctuation spectrum of a fluid membrane coupled harmonically to a solid support by an array of tethers is calculated. For strong tethers, this spectrum exhibits non-monotonic, anisotropic behavior with a relative maximum at a…

Soft Condensed Matter · Physics 2008-12-08 Rolf-Juergen Merath , Udo Seifert

The origin of nonthermal broadening in solar spectra is one of the long-standing questions in solar physics. Various processes have been invoked - including unresolved flows, waves, and turbulent processes - but definitive answers are…

Solar and Stellar Astrophysics · Physics 2024-10-28 Kyuhyoun Cho , Bart De Pontieu , Paola Testa

Registering periodic variations of spectral line widths serves as the main method for observing torsional Alfv\'{e}n waves. Theoretically, the method seems valid, yet it entails a number of caveats when applied to data. For instance, the…

Solar and Stellar Astrophysics · Physics 2022-12-29 A. A. Chelpanov , N. I. Kobanov

Numerical simulations shed light onto earlier not trackable problem of magnetohydrodynamic (MHD) turbulence. They allowed to test the predictions of different models and choose the correct ones. Inevitably, this progress calls for revisions…

Astrophysics · Physics 2007-12-27 Huirong Yan , A. Lazarian