Slow-mode oscillations of large-scale coronal loops

Solar Physics ◽  
1994 ◽  
Vol 152 (2) ◽  
pp. 505-508 ◽  
Author(s):  
Zdeněk Švestka
Keyword(s):  
Large Scale ◽  
Coronal Loops ◽  
Slow Mode

scholarly journals Coronal global EIT waves as tools for multiple diagnostics

2007 ◽  
Vol 3 (S247) ◽  
pp. 243-250
Author(s):  
I. Ballai ◽  
M. Douglas
Keyword(s):  
Magnetic Field ◽  
Solar Corona ◽  
Solar Disk ◽  
Coronal Loop ◽  
Large Scale ◽  
Theoretical Models ◽  
Coronal Loops ◽  
Quiet Sun ◽  
Propagating Waves ◽  
Global Magnetic Field

AbstractObservations in EUV lines of the solar corona revealed large scale propagating waves generated by eruptive events able to travel across the solar disk for large distances. In the low corona, CMEs are known to generate, e.g. EIT waves which can be used to sample the coronal local and global magnetic field. This contribution presents theoretical models for finding values of magnetic field in the quiet Sun and coronal loops based on the interaction of global waves and local coronal loops as well as results on the generation and propagation of EIT waves. The physical connection between local and global solar coronal events (e.g. flares, EIT waves and coronal loop oscillations) will also be explored.

scholarly journals Damping of standing slow waves in hot coronal loops

2007 ◽  
Vol 3 (S247) ◽  
pp. 303-311
Author(s):  
Leonardo Di G. Sigalotti ◽  
César A. Mendoza-Briceño ◽  
Marialejandra Luna-Cardozo
Keyword(s):  
Energy Dissipation ◽  
Viscous Dissipation ◽  
Thermal Conduction ◽  
Slow Waves ◽  
Coronal Loops ◽  
Slow Mode ◽  
Decay Times ◽  
Crossing Time ◽  
Linear Limit ◽  
Radiative Losses

AbstractThe damping of standing slow mode oscillations in hot (T > 6 MK) coronal loops is described in the linear limit. The effects of energy dissipation by thermal conduction, viscosity, and radiative losses and gains are examined for both stratified and nonstratified loops. We find that thermal conduction acts on the way of increasing the period of the oscillations over the sound crossing time, whereas the decay times are mostly determined by viscous dissipation. Thermal conduction alone results in slower damping of the density and velocity waves compared to the observations. Only when viscosity is added do these waves damp out at the same rate of the observed SUMER loop oscillations. In the linear limit, the periods and decay times are barely affected by gravity.

scholarly journals Shock heating in numerical simulations of kink-unstable coronal loops

2015 ◽  
Vol 373 (2042) ◽  
pp. 20140266 ◽  
Author(s):  
M. R. Bareford ◽  
A. W. Hood
Keyword(s):  
Magnetic Reconnection ◽  
Large Scale ◽  
Magnetic Energy ◽  
Coronal Loops ◽  
Current Sheets ◽  
Shock Heating ◽  
Strong Current ◽  
Coronal Magnetic Fields ◽  
Magnetohydrodynamic Simulations ◽  
The Magnetic Field

An analysis of the importance of shock heating within coronal magnetic fields has hitherto been a neglected area of study. We present new results obtained from nonlinear magnetohydrodynamic simulations of straight coronal loops. This work shows how the energy released from the magnetic field, following an ideal instability, can be converted into thermal energy, thereby heating the solar corona. Fast dissipation of magnetic energy is necessary for coronal heating and this requirement is compatible with the time scales associated with ideal instabilities. Therefore, we choose an initial loop configuration that is susceptible to the fast-growing kink, an instability that is likely to be created by convectively driven vortices, occurring where the loop field intersects the photosphere (i.e. the loop footpoints). The large-scale deformation of the field caused by the kinking creates the conditions for the formation of strong current sheets and magnetic reconnection, which have previously been considered as sites of heating, under the assumption of an enhanced resistivity. However, our simulations indicate that slow mode shocks are the primary heating mechanism, since, as well as creating current sheets, magnetic reconnection also generates plasma flows that are faster than the slow magnetoacoustic wave speed.

scholarly journals Structure of solar coronal loops: from miniature to large-scale

2013 ◽  
Vol 556 ◽  
pp. A104 ◽  
Author(s):  
H. Peter ◽  
S. Bingert ◽  
J. A. Klimchuk ◽  
C. de Forest ◽  
J. W. Cirtain ◽  
...  
Keyword(s):  
Large Scale ◽  
Coronal Loops ◽  
Solar Coronal

scholarly journals Possible manifestation of large-scale transverse oscillations of coronal loops in solar microwave emission

2010 ◽  
Vol 525 ◽  
pp. A105 ◽  
Author(s):  
M. L. Khodachenko ◽  
K. G. Kislyakova ◽  
T. V. Zaqarashvili ◽  
A. G. Kislyakov ◽  
M. Panchenko ◽  
...  
Keyword(s):  
Large Scale ◽  
Microwave Emission ◽  
Coronal Loops ◽  
Solar Microwave ◽  
Transverse Oscillations

Slow magnetohydrodynamic waves in the solar atmosphere

2005 ◽  
Vol 364 (1839) ◽  
pp. 447-460 ◽  
Author(s):  
B Roberts
Keyword(s):  
Solar Atmosphere ◽  
Gordon Equation ◽  
Observational Evidence ◽  
Stratified Medium ◽  
Coronal Loops ◽  
Slow Mode ◽  
Magnetohydrodynamic Equations ◽  
Magnetohydrodynamic Waves ◽  
Klein Gordon ◽  
Special Case

There is increasingly strong observational evidence that slow magnetoacoustic modes arise in the solar atmosphere, either as propagating or standing waves. Sunspots, coronal plumes and coronal loops all appear to support slow modes. Here we examine theoretically how the slow mode may be extracted from the magnetohydrodynamic equations, considering the special case of a vertical magnetic field in a stratified medium: the slow mode is described by the Klein–Gordon equation. We consider its application to recent observations of slow waves in coronal loops.

scholarly journals Slow-mode standing waves observed by SUMER in hot coronal loops

2003 ◽  
Vol 402 (2) ◽  
pp. L17-L20 ◽  
Author(s):  
T. J. Wang ◽  
S. K. Solanki ◽  
D. E. Innes ◽  
W. Curdt ◽  
E. Marsch
Keyword(s):  
Standing Waves ◽  
Coronal Loops ◽  
Slow Mode
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