Radiative damping of gravity waves in the solar atmosphere

1980 ◽  
Vol 27 (3-4) ◽  
Author(s):  
JerryD. Logan ◽  
HenryA. Hill
Keyword(s):  
Solar Atmosphere ◽  
Gravity Waves ◽  
Radiative Damping

Radiative damping of trapped gravity waves in the solar atmosphere

Solar Physics ◽  
1973 ◽  
Vol 30 (2) ◽  
pp. 319-325 ◽  
Author(s):  
Patricia André Clark ◽  
Alfred Clark
Keyword(s):  
Solar Atmosphere ◽  
Gravity Waves ◽  
Radiative Damping

scholarly journals Radiative Damping of Gravity Waves in the Solar Atmosphere

1980 ◽  
Vol 58 ◽  
pp. 301-306
Author(s):  
Jerry D. Logan ◽  
Henry A. Hill
Keyword(s):  
Radiation Field ◽  
Solar Atmosphere ◽  
Gravity Waves ◽  
Driving Mechanism ◽  
Solar Photosphere ◽  
Nonlocal Effects ◽  
Newtonian Approximation ◽  
Radiative Damping ◽  
Low Order

AbstractThe nonlocal character of the radiation field sinnificantly modifies the radiative damping of perturbations in the solar photosphere. Gravity waves are not usually considered to exist in the solar photosphere because the radiative damping time, when based on the Newtonian approximation, is too short. However, this restriction does not apply to low order gravity waves. In fact, with the inclusion of nonlocal effects, the radiative damping for low order gravity waves becomes negative for some region in the photosphere and thus acts as a driving mechanism for gravity waves there.

scholarly journals Synthetic observations of internal gravity waves in the solar atmosphere

2020 ◽  
Vol 633 ◽  
pp. A140
Author(s):  
G. Vigeesh ◽  
M. Roth
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Solar Atmosphere ◽  
Energy Flux ◽  
Gravity Waves ◽  
Internal Gravity Waves ◽  
Spectral Lines ◽  
Magnetic Flux Density ◽  
Phase Differences

Aims. We study the properties of internal gravity waves (IGWs) detected in synthetic observations that are obtained from realistic numerical simulation of the solar atmosphere. Methods. We used four different simulations of the solar magneto-convection performed using the CO5BOLD code. A magnetic-field-free model and three magnetic models were simulated. The latter three models start with an initial vertical, homogeneous field of 10, 50, and 100 G magnetic flux density, representing different regions of the quiet solar surface. We used the NICOLE code to compute synthetic spectral maps from all the simulated models for the two magnetically insensitive neutral iron lines Fe I λλ 5434 Å and 5576 Å. We carried out Fourier analyses of the intensity and Doppler velocities to derive the power, phase, and coherence in the kh − ω diagnostic diagram to study the properties of internal gravity waves. Results. We find the signatures of the internal gravity waves in the synthetic spectra to be consistent with observations of the real Sun. The effect of magnetic field on the wave spectra is not as clearly discernible in synthetic observations as in the case of numerical simulations. The phase differences obtained using the spectral lines are significantly different from the phase differences in the simulation. The phase coherency between two atmospheric layers in the gravity wave regime is height dependent and is seen to decrease with the travel distance between the observed layers. In the studied models, the lower atmosphere shows a phase coherency above the significance level for a height separation of ∼400 km, while in the chromospheric layers it reduces to ∼100–200 km depending on the average magnetic flux density. Conclusion. We conclude that the energy flux of IGWs determined from the phase difference analysis may be overestimated by an order of magnitude. Spectral lines that are weak and less temperature sensitive may be better suited to detecting internal waves and accurately determining their energy flux in the solar atmosphere.

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