Asymmetries of solar oscillation line profiles
Asymmetries of solar oscillation line profiles
复制标题
太阳振荡线剖面的不对称性
DOI：
10.1086/172800
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
M. Pomerantz
中科院分区：
文献类型：
--
作者：
T. Duvall;S. Jefferies;J. Harvey;Y. Osaki;M. Pomerantz
在对Ca II K Fraunhofer谱线进行的全圆盘强度观测中，发现了太阳全局p模功率谱线轮廓的不对称性。不对称性是时间频率的强函数，在观察到的最低频率处最强，并且在功率分布的峰值附近消失。球谐度的变化较小。的不对称性解释的模型中，太阳振荡腔相比，法布里-珀罗干涉仪的源稍微外的腔。向外的直接波和穿过空腔的对应向内的波之间的相位差引起不对称性。这种不对称性在速度和强度观测中是不同的。在对功率谱建模时忽略不对称性会导致模频率测量中的系统误差高达模频率的10 exp-4。目前的观测和解释将振荡源定位在光球之下约60公里处，这是迄今为止建议的最浅位置。
Asymmetries of the power spectral line profiles of solar global p-modes are detected in full-disk intensity observations of the Ca II K Fraunhofer line. The asymmetry is a strong function of temporal frequency being strongest at the lowest frequencies observed and vanishing near the peak of the power distribution. The variation with spherical harmonic degree is small. The asymmetry is interpreted in terms of a model in which the solar oscillation cavity is compared to a Fabry-Perot interferometer with the source slightly outside the cavity. A phase difference between an outward direct wave and a corresponding inward wave that passes through the cavity gives rise to the asymmetry. The asymmetry is different in velocity and intensity observations. Neglecting the asymmetry when modeling the power spectrum can lead to systematic errors in the measurement of mode frequencies of as much as 10 exp -4 of the mode frequency. The present observations and interpretation locate the source of the oscillations to be approximately 60 km beneath the photosphere, the shallowest position suggested to date.