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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

Aims: This paper presents 2.5D numerical experiments of Alfv\'en wave phase mixing and aims to assess the effects of nonlinearities on wave behaviour and dissipation. In addition, this paper aims to quantify how effective the model…

Solar and Stellar Astrophysics · Physics 2019-04-17 Alexander Prokopyszyn , Alan Hood , Ineke De Moortel

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

It is extremely difficult to simulate the details of coronal heating and also make meaningful predictions of the emitted radiation. Thus, testing realistic models with observations is a major challenge. Observational signatures of coronal…

Solar and Stellar Astrophysics · Physics 2022-11-02 James A. Klimchuk , Kalman J. Knizhnik , Vadim M. Uritsky

Spectral line widths are often observed to be larger than can be accounted for by thermal and instrumental broadening alone. This excess broadening is a key observational constraint for both nanoflare and wave dissipation models of coronal…

Solar and Stellar Astrophysics · Physics 2016-03-23 David H. Brooks , Harry P. Warren

Here we investigate the contribution of surface Alfven wave damping to the heating of the solar wind in minima conditions. These waves are present in regions of strong inhomogeneities in density or magnetic field (e. g., the border between…

Solar and Stellar Astrophysics · Physics 2015-05-14 R. M. Evans , M. Opher , V. Jatenco-Pereira , T. I. Gombosi

State-of-the-art MHD calculations reveal acceptable agreement with observational data for the height profile of the temperature $T(h)$ in the transition region of solar corona. Simultaneously, the velocity of the solar wind $U(h)$ has also…

Plasma Physics · Physics 2020-07-29 A. M. Varonov

We solve numerically ideal, 2.5D, MHD equations in Cartesian coordinates, with a plasma beta of 0.0001 starting from the equilibrium that mimics a footpoint of a large curvature radius solar coronal loop or a polar region plume. On top of…

Astrophysics · Physics 2007-05-23 David Tsiklauri

Magnetic arcades in the solar atmosphere, or coronal loops, are common structures known to host magnetohydrodynamic (MHD) waves and oscillations. Of particular interest are the observed properties of transverse loop oscillations, such as…

Solar and Stellar Astrophysics · Physics 2021-06-16 Farhad Allian , Rekha Jain

Acoustic waves are one of the primary suspects besides magnetic fields for the chromospheric heating process to temperatures above radiative equilibrium (RE). We derived the mechanical wave energy as seen in line-core velocities to obtain a…

Solar and Stellar Astrophysics · Physics 2015-05-13 C. Beck , E. Khomenko , R. Rezaei , M. Collados

Ultraviolet spectroscopy of the extended solar corona is a powerful tool for measuring the properties of protons, electrons, and heavy ions in the accelerating solar wind. The large coronal holes that expand up from the north and south…

Solar and Stellar Astrophysics · Physics 2020-07-28 Steven R. Cranmer

A simplified non-linear numerical model for the development of incompressible magnetohydrodynamics (MHD) in the presence of a strong magnetic field B0 and stratification, nicknamed Shell-Atm, is presented. In planes orthogonal to the mean…

Astrophysics · Physics 2011-02-11 E. Buchlin , M. Velli

Aims. We investigate the formation of small scales and the dissipation of MHD wave energy through non-linear interactions of counter-propagating, phase-mixed Alfvenic waves in a complex magnetic field. Methods. We conducted fully 3-D,…

Solar and Stellar Astrophysics · Physics 2020-04-15 Thomas Howson , Ineke De Moortel , Jack Reid

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

We perform magnetohydrodynamic (MHD) simulations to investigate the propagation of Alfven wave in magnetic chromosphere. We use the 1.5-dimensional expanding flux tube geometry setting and transverse perturbation at the bottom to generate…

Solar and Stellar Astrophysics · Physics 2020-03-13 Yikang Wang , Takaaki Yokoyama

We numerically investigate the excitation and temporal evolution of oscillations in a two-dimensional coronal arcade by including the three-dimensional propagation of perturbations. The time evolution of impulsively generated perturbations…

Solar and Stellar Astrophysics · Physics 2015-05-18 S. Rial , I. Arregui , J. Terradas , R. Oliver , J. L. Ballester

We solve numerically the ideal MHD equations with an external gravitational field in 2D in order to study the effects of impulsively generated linear and non-linear Alfv\'en waves into isolated solar arcades and coronal funnels. We analyze…

Solar and Stellar Astrophysics · Physics 2015-09-23 J. J. Gonzalez-Aviles , F. S. Guzman

We present a new global model of the solar corona, including the low corona, the transition region and the top of chromosphere. The realistic 3D magnetic field is simulated using the data from the photospheric magnetic field measurements.…

Knowledge of the structure of the coronal magnetic field is important for our understanding of many solar activity phenomena, e.g. flares and CMEs. However, the direct measurement of coronal magnetic fields is not possible with present…

Astrophysics · Physics 2020-01-29 T. Wiegelmann , T. Neukirch

Aims. The goal is to employ a 3D magnetohydrodynamics (MHD) model including spectral synthesis to model the corona in an observed solar active region. This will allow us to judge the merits of the coronal heating mechanism built into the 3D…

Solar and Stellar Astrophysics · Physics 2017-09-19 Ph. -A. Bourdin , S. Bingert , H. Peter