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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

We revisit in more detail a model for element abundance fractionation in the solar chromosphere, that gives rise to the "FIP Effect" in the solar corona and wind. Elements with first ionization potential below about 10 eV, i.e. those that…

Solar and Stellar Astrophysics · Physics 2014-11-18 J. Martin Laming

We investigate the difference in the spatial distribution of the energy input for parametrizations of different mechanisms to heat the corona of the Sun and possible impacts on the coronal emission. We use a 3D MHD model of a solar active…

Solar and Stellar Astrophysics · Physics 2015-06-15 T. van Wettum , S. Bingert , H. Peter

Over decades of solar wind observations, heavy ions have been observed to have a higher temperature and flow faster than protons in the solar corona and heliosphere. Remote observations have largely been limited to the low corona ($<…

We perform numerical simulations of impulsively generated Alfv\'en waves in an isolated solar arcade, which is gravitationally stratified and magnetically confined. We study numerically the propagation of Alfv\'en waves along such magnetic…

Solar and Stellar Astrophysics · Physics 2015-06-22 P. Chmielewski , K. Murawski , Z. E. Musielak , A. K. Srivastava

M dwarf's atmosphere and wind is expected to be highly magnetized. The nonlinear propagation of Alfv\'en wave could play a key role in both heating the stellar atmosphere and driving the stellar wind. Along this Alfv\'en wave scenario, we…

Solar and Stellar Astrophysics · Physics 2021-01-20 Takahito Sakaue , Kazunari Shibata

Minor ion (such as $He^{2+}$) heating via nonresonant interaction with spectra of linearly and circularly polarized Alfv\'{e}n waves (LPAWs and CPAWs hereafter) is studied. The obtained analytic solutions are in good agreement with the…

Solar and Stellar Astrophysics · Physics 2015-06-18 Chuanfei Dong

Alfv\'en waves play three related roles in the impulsive phase of a solar flare: they transport energy from a generator region to an acceleration region; they map the cross-field potential (associated with the driven energy release) from…

Solar and Stellar Astrophysics · Physics 2015-06-15 D. B. Melrose , M. S. Wheatland

Turbulence in an accretion disk launches Alfv\'en waves (AWs) that propagate away from the disk along magnetic field lines. Because the Alfv\'en speed varies with distance from the disk, the AWs undergo partial non-WKB reflection, and…

High Energy Astrophysical Phenomena · Physics 2018-07-18 Benjamin D. G. Chandran , Francois Foucart , Alexander Tchekhovskoy

The solar transition region (TR), in which above the photosphere the tempera- ture increases rapidly and the density drops dramatically, is believed to play an important role in coronal heating and solar wind acceleration. Long-lasting…

Solar and Stellar Astrophysics · Physics 2017-08-02 H. Tian , W. Curdt , J. -S. He

We present a new insight into the propagation, attenuation and dissipation of two-fluid, torsional Alfv\'en waves in the context of heating of the lower solar atmosphere. By means of numerical simulations of the partially-ionized plasma, we…

Solar and Stellar Astrophysics · Physics 2022-11-23 B. Kuźma , K. Murawski , S. Poedts

Kink oscillations of a coronal loop are observed and studied in detail because they provide a unique probe into the structure of coronal loops through MHD seismology and a potential test of coronal heating through the phase-mixing of…

Solar and Stellar Astrophysics · Physics 2018-08-29 P. Pagano , D. J. Pascoe , I. De Moortel

The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal…

Solar and Stellar Astrophysics · Physics 2017-10-11 Steven R. Cranmer , Sarah E. Gibson , Pete Riley

We consider ion heating by turbulent Alfven waves (AWs) and kinetic Alfven waves (KAWs) with perpendicular wavelengths comparable to the ion gyroradius and frequencies smaller than the ion cyclotron frequency. When the turbulence amplitude…

Solar and Stellar Astrophysics · Physics 2015-05-14 Benjamin D. G. Chandran , Bo Li , Barrett N. Rogers , Eliot Quataert , Kai Germaschewski

Alfv\'enic waves have gained renewed interest since the existence of ubiquitous propagating kink waves were discovered in the corona. {It has long been suggested that Alfv\'enic} waves play an important role in coronal heating and the…

Solar and Stellar Astrophysics · Physics 2019-05-15 Ajay K. Tiwari , Richard J. Morton , Stephane Régnier , James A. McLaughlin

The presence and interplay of continuous cooling and heating processes maintaining the corona of the Sun at the observed one million K temperature were recently understood to have crucial effects on the dynamics and stability of…

Solar and Stellar Astrophysics · Physics 2021-12-16 D. Y. Kolotkov , D. I. Zavershinskii , V. M. Nakariakov

Cool stars at giant and supergiant evolutionary phases present low velocity and high density winds, responsible for the observed high mass-loss rates. Although presenting high luminosities, radiation pressure on dust particles is not…

Astrophysics · Physics 2009-11-11 D. Falceta-Goncalves , A. A. Vidotto , V. Jatenco-Pereira

Analyses of the widths and shifts of optically thin emission lines in the ultraviolet spectrum of the active dwarf Epsilon Eri (K2 V) are presented. The spectra were obtained using the Space Telescope Imaging Spectrograph on the Hubble…

Astrophysics · Physics 2008-11-26 S. A. Sim , C. Jordan

Modelling the solar Transition Region with the use of an Adaptive Conduction (TRAC) method permits fast and accurate numerical solutions of the field-aligned hydrodynamic equations, capturing the enthalpy exchange between the corona and…

Solar and Stellar Astrophysics · Physics 2020-04-01 C. D. Johnston , P. J. Cargill , A. W. Hood , I. De Moortel , S. J. Bradshaw , A. C. Vaseekar

We explore a mechanism, entirely new to the fast solar wind, of electron heating by lower hybrid waves to explain the shift to higher charge states observed in various elements in the fast wind at 1 A.U. relative to the original coronal…

Astrophysics · Physics 2009-11-10 J. Martin Laming