Astronomy and Astrophysics – Astronomy
Scientific paper
Oct 2009
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009acasn..50..349x&link_type=abstract
Acta Astronomica Sinica, vol. 50, no. 4, p. 349-355
Astronomy and Astrophysics
Astronomy
Convection, Sun: Oscillations
Scientific paper
The excitation mechanism of solar five-minute oscillations is studied in this paper. We calculated the non-adiabatic oscillations of low- and intermediate-degree (l=1-25) g4-p39 modes for the Sun. Both the thermodynamic and dynamic couplings are taken into account by using our non-local and time-dependent theory of convection. The results show that all the low-frequency f- and p-modes with periods P>5.4 minutes are pulsationally unstable, while the coupling between convection and oscillations is neglected. However, when the convection coupling is taken into account, all the g- and low-frequency f- and p-modes with periods longer than ~16 minutes (except the low-degree p1-modes) and the high frequency p-modes with periods shorter than ~3 minutes become stable, and the intermediate-frequency p-modes with period from ~3 to ~16 minutes are pulsationally unstable. The pulsation amplitude growth rates depend only on the frequency and almost do not depend on ℓ. They achieve the maximum at ν~3700 μHz (P~2700 seconds). The coupling between convection and oscillations plays a key role for stabilization of low-frequency f- and p-modes and excitation of intermediate-frequency p-modes. We propose that the solar 5-minute oscillations are not caused by any single excitation mechanism, but they are resulted from the combined effect of "regular" coupling between convection and oscillations and turbulent stochastic excitation. For low- and intermediate-frequency p-modes, the coupling between convection and oscillations dominates; while for high-frequency modes, stochastic excitation dominates.
Deng Li Cai
Xiong Da-Run
No associations
LandOfFree
On the Excitation Mechanism of Solar Five-minute Oscillations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with On the Excitation Mechanism of Solar Five-minute Oscillations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the Excitation Mechanism of Solar Five-minute Oscillations will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-804532