Oscillatory Response of the 3D Solar Atmosphere to the Leakage of Photospheric Motion
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The direct propagation of acoustic waves, driven harmonically at the solar photosphere, into the three-dimensional solar atmosphere is examined numerically in the framework of ideal magnetohydrodynamics. It is of particular interest to study the leakage of 5-minute global solar acoustic oscillations into the upper, gravitationally stratified and magnetised atmosphere, where the modelled solar atmosphere possesses realistic temperature and density stratification. This work aims to complement and bring further into the 3D domain our previous efforts (by Erdélyi et al., 2007, Astron. Astrophys. 467, 1299) on the leakage of photospheric motions and running magnetic-field-aligned waves excited by these global oscillations. The constructed model atmosphere, most suitable perhaps for quiet Sun regions, is a VAL IIIC derivative in which a uniform magnetic field is embedded. The response of the atmosphere to a range of periodic velocity drivers is numerically investigated in the hydrodynamic and magnetohydrodynamic approximations. Among others the following results are discussed in detail: i) High-frequency waves are shown to propagate from the lower atmosphere across the transition region, experiencing relatively low reflection, and transmitting most of their energy into the corona; ii) the thin transition region becomes a wave guide for horizontally propagating surface waves for a wide range of driver periods, and particularly at those periods that support chromospheric standing waves; iii) the magnetic field acts as a waveguide for both high- and low-frequency waves originating from the photosphere and propagating through the transition region into the solar corona.
KeywordsMagnetic flux tube MHD waves Solar atmosphere
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- Aschwanden, M.: 2004, Physics of the Solar Corona. An Introduction, Praxis, Chichester. Google Scholar
- Bogdan, T., Carlsson, M., Hansteen, V., McMurry, A., Rosenthal, C., Johnson, M., Petty-Powell, S., Zita, E., Stein, R., McIntosh, S., Nordlund, Å.: 2003, Waves in the magnetized solar atmosphere. II. Waves from localized sources in magnetic flux concentrations. Astrophys. J. 599, 626. CrossRefADSGoogle Scholar
- Finsterle, W., Haberreiter, M., Kosovichev, S., Schmutz, W.: 2008, P-mode leakage and Lyman-α intensity. In: Erdélyi, R., Mendoza-Brice no, C.A. (eds.) Waves and Oscillations in the Solar Atmosphere: Heating and Magneto-Seismology. Proceedings of the International Astronomical Union, IAU Symp. 247, 74. Google Scholar
- Hansteen, V., Carlsson, M., Gudiksen, B.: 2007, 3D numerical models of the chromosphere, transition region, and corona. In: Heinzel, P., Dorotovic, I., Rutten, R.J. (eds.) The Physics of Chromospheric Plasmas CS-368, Astron. Soc. Pac., San Francisco, 107. Google Scholar
- McDougall, A.M.D., Hood, A.W.: 2008, MHD mode conversion in a stratified atmosphere. In: Erdélyi, R., Mendoza-Briceno, C.A. (eds.) Waves and Oscillations in the Solar Atmosphere: Heating and Magneto-Seismology. Proceedings of the International Astronomical Union, IAU Symp. 247, 296. Google Scholar
- Nordlund, Å., Galsgaard, K.: 1995, A 3D MHD code for parallel computers. Tech. Rep., Astron. Obs. Univ. Copenhagen. Google Scholar
- Roberts, B.: 2004, MHD waves in the solar atmosphere. In: Waves, Oscillations and Small-Scale Transients Events in the Solar Atmosphere: Joint View from SOHO and TRACE, Proceedings of SOHO 13 547, 1. Google Scholar