| タイトル | Linear models of acoustic waves in sunspot umbrae |
| 著者（英） | Leibacher, J. W.; Gurman, J. B. |
| 著者所属（英） | NASA Goddard Space Flight Center|Arizona Univ.|Applied Research Corp. |
| 発行日 | 1984-08-15 |
| 言語 | eng |
| 内容記述 | The two-dimensional, linear hydrodynamics of quiet solar and umbral model atmospheres in a plane-parallel, adiabatic approximation are investigated. The 5.5-8.5 mHz oscillations observed in umbral chromospheres and transition regions are interpreted as acoustic waves propagating parallel, or nearly parallel, to the temperature gradient. These waves are not totally internally reflected by the steep temperature gradient and, thus, are not trapped. Partial reflections, however, are effective in modulating the transmission as a function of frequency. The resonant transmission mechanism of Zugzda, Locans, and Staude (1983) is found to produce a spectrum of resonances in the transmission of acoustic waves in any atmosphere with a temperature minimum. Since the observed umbral oscillations display power in only a narrow range of frequencies, characteristics of the umbral models, wave propagation, and observations that would tend to suppress the higher frequency resonances are examined. |
| NASA分類 | SOLAR PHYSICS |
| レポートNO | 84A47944 |
| 権利 | Copyright |
| URI | https://repository.exst.jaxa.jp/dspace/handle/a-is/396358 |
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