MHD waves at a spherical interface modelling EIT waves

2007 ◽  
Vol 328 (8) ◽  
pp. 769-772 ◽  
Author(s):  
M. Douglas ◽  
I. Ballai
Keyword(s):  
Mhd Waves ◽  
Spherical Interface

scholarly journals MHD waves at a spherical interface modelling coronal global EIT waves

2007 ◽  
Vol 3 (S247) ◽  
pp. 251-254
Author(s):  
M. Douglas ◽  
I. Ballai
Keyword(s):  
Magnetic Field ◽  
Coronal Mass Ejections ◽  
Solar Radius ◽  
Mhd Waves ◽  
Density Interface ◽  
Spherical Interface ◽  
Coronal Dimming

AbstractEnergetically eruptive events such as flares and coronal mass ejections (CMEs) are known to generate global waves, propagating over large distances, sometimes comparable to the solar radius. In this contribution EIT waves are modelled as waves propagating at a spherical density interface in the presence of a radially expanding magnetic field. The generation and propagation of EIT waves is studied numerically for coronal parameters. Simple equilibria allow the explanation of the coronal dimming caused by EIT waves as a region of rarified plasma created by a siphon flow.

Linear Visco-Resistive Computations of Magnetohydrodynamic Waves: I. The Code and Test Cases

1994 ◽  
Vol 144 ◽  
pp. 503-505
Author(s):  
R. Erdélyi ◽  
M. Goossens ◽  
S. Poedts
Keyword(s):  
Resonant Absorption ◽  
Numerical Code ◽  
Mhd Waves ◽  
Test Cases ◽  
Numerical Accuracy ◽  
Element Discretization ◽  
Flux Tubes ◽  
Magnetohydrodynamic Waves ◽  
Viscosity Coefficients ◽  
Magnetic Flux Tubes

AbstractThe stationary state of resonant absorption of linear, MHD waves in cylindrical magnetic flux tubes is studied in viscous, compressible MHD with a numerical code using finite element discretization. The full viscosity tensor with the five viscosity coefficients as given by Braginskii is included in the analysis. Our computations reproduce the absorption rates obtained by Lou in scalar viscous MHD and Goossens and Poedts in resistive MHD, which guarantee the numerical accuracy of the tensorial viscous MHD code.

Theory of low-scale mhd waves in the near equatorial region of the earth plasmasphere

2001 ◽  
Vol 7 (2s) ◽  
pp. 74-83
Author(s):  
O.S. Burdo ◽  
◽  
O.K. Cheremnykh ◽  
O.P. Verkhoglyadova ◽  
◽  
...  
Keyword(s):  
Equatorial Region ◽  
Mhd Waves ◽  
The Earth

Non-Linear Interaction of MHD Waves with Small-Scale Ionospheric Irregularities

2004 ◽  
Vol 61 (7-12) ◽  
pp. 1055-1071
Author(s):  
N. N. Gerasimova ◽  
V. G. Sinitsin ◽  
Yu. M. Yampolski
Keyword(s):  
Ionospheric Irregularities ◽  
Mhd Waves ◽  
Small Scale ◽  
Linear Interaction ◽  
Non Linear

Influence of thermal conduction on MHD waves properties in thermally unstable plasma

2016 ◽  
Vol 52 (1-2) ◽  
pp. 199-208 ◽  
Author(s):  
N. E. Molevich ◽  
D. S. Ryashchikov ◽  
D. I. Zavershinskiy
Keyword(s):  
Thermal Conduction ◽  
Mhd Waves ◽  
Unstable Plasma

scholarly journals Dispersive MHD waves and alfvenons in charge non-neutral plasmas

2008 ◽  
Vol 15 (4) ◽  
pp. 681-693 ◽  
Author(s):  
K. Stasiewicz ◽  
J. Ekeberg
Keyword(s):  
Soliton Solutions ◽  
Theoretical Models ◽  
Mhd Waves ◽  
Space Plasmas ◽  
Charge Effects ◽  
Novel Technique ◽  
Solitary Structures ◽  
Spatial Dimensions ◽  
Electric Potentials ◽  
Linear And Nonlinear

Abstract. Dispersive properties of linear and nonlinear MHD waves, including shear, kinetic, electron inertial Alfvén, and slow and fast magnetosonic waves are analyzed using both analytical expansions and a novel technique of dispersion diagrams. The analysis is extended to explicitly include space charge effects in non-neutral plasmas. Nonlinear soliton solutions, here called alfvenons, are found to represent either convergent or divergent electric field structures with electric potentials and spatial dimensions similar to those observed by satellites in auroral regions. Similar solitary structures are postulated to be created in the solar corona, where fast alfvenons can provide acceleration of electrons to hundreds of keV during flares. Slow alfvenons driven by chromospheric convection produce positive potentials that can account for the acceleration of solar wind ions to 300–800 km/s. New results are discussed in the context of observations and other theoretical models for nonlinear Alfvén waves in space plasmas.

Sausage MHD Waves in Incompressible Flux Tubes with Twisted Magnetic Fields

Solar Physics ◽  
2006 ◽  
Vol 238 (1) ◽  
pp. 41-59 ◽  
Author(s):  
Robert Erdélyi ◽  
Viktor Fedun
Keyword(s):  
Magnetic Fields ◽  
Mhd Waves ◽  
Flux Tubes

scholarly journals High resolution observations of spectral width features associatedwith ULF wave signatures in artificial HF radar backscatter

2004 ◽  
Vol 22 (1) ◽  
pp. 169-182 ◽  
Author(s):  
D. M. Wright ◽  
T. K. Yeoman ◽  
L. J. Baddeley ◽  
J. A. Davies ◽  
R. S. Dhillon ◽  
...  
Keyword(s):  
High Resolution ◽  
Plasma Source ◽  
Spectral Width ◽  
Hf Radar ◽  
Mhd Waves ◽  
Small Scale ◽  
Ulf Waves ◽  
Source Population ◽  
Radar Backscatter ◽  
Field Lines

Abstract. The EISCAT high power heating facility at Tromsø, northern Norway, has been utilised to generate artificial radar backscatter in the fields of view of the CUTLASS HF radars. It has been demonstrated that this technique offers a means of making very accurate and high resolution observations of naturally occurring ULF waves. During such experiments, the usually narrow radar spectral widths associated with artificial irregularities increase at times when small scale-sized (high m-number) ULF waves are observed. Possible mechanisms by which these particle-driven high-m waves may modify the observed spectral widths have been investigated. The results are found to be consistent with Pc1 (ion-cyclotron) wave activity, causing aliasing of the radar spectra, in agreement with previous modelling work. The observations also support recent suggestions that Pc1 waves may be modulated by the action of longer period ULF standing waves, which are simultaneously detected on the magnetospheric field lines. Drifting ring current protons with energies of ∼ 10keV are indicated as a common plasma source population for both wave types. Key words. Magnetospheric physics (MHD waves and instabilities) – Space plasma physics (wave-particle interactions) – Ionosphere (active experiments)

scholarly journals Prominence Seismology

2013 ◽  
Vol 8 (S300) ◽  
pp. 30-39 ◽  
Author(s):  
J. L. Ballester
Keyword(s):  
Solar Corona ◽  
Small Amplitude ◽  
Dense Plasma ◽  
Mhd Waves ◽  
Physical Parameters ◽  
Solar Prominences ◽  
Dynamic Structures

AbstractQuiescent solar prominences are cool and dense plasma clouds located inside the hot and less dense solar corona. They are highly dynamic structures displaying flows, instabilities, oscillatory motions, etc. The oscillations have been mostly interpreted in terms of magnetohydrodynamic (MHD) waves, which has allowed to perform prominence seismology as a tool to determine prominence physical parameters difficult to measure. Here, several prominence seismology applications to large and small amplitude oscillations are reviewed.

Effect of the ionosphere on the propagation of beams of MHD waves

1984 ◽  
Vol 27 (10) ◽  
pp. 864-872
Author(s):  
L. S. Al'perovich ◽  
E. N. Fedorov
Keyword(s):  
Mhd Waves
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