Seismology of the solar envelope: measuring the acoustic phase shift generated in the outer layers
Seismology of the solar envelope: measuring the acoustic phase shift generated in the outer layers
复制标题
太阳外壳的地震学：测量外层产生的声相移
DOI：
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
S. Vorontsov
中科院分区：
文献类型：
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作者：
D. Gough;S. Vorontsov
由快速空间变化的区域的声波的部分反射以通常根据声学相位α描述的方式调制太阳p模式频率。在低程度上，a仅是频率的函数。在更高的度数处，从法线到反射层的声线路径的倾斜变得显著，并且产生度数依赖性。在目前频率测量精度的情况下，这种现象对于对流区中捕获的所有p模式都是重要的。我们描述了一种技术，能够分离度相关的组件从领先的长期a0（cd）。我们确定的领导阶贡献的程度依赖的a从太阳的p-模式的频率报告的Libbrecht，Woodard和考夫曼，并比较结果与直接计算的太阳能模型的基础上所描述的Brodsky和Vorontsov的形式主义。主要贡献来自第二氦电离区，并可作为一个新的信息源有关的日震校准的状态方程的太阳等离子体和太阳氦丰度的测定。
Partial reflection of acoustic waves by regions of rapid spatial variation modulates the solar p-mode frequencies, in a manner that is often described in terms of an acoustic phase a. At low degree, a is a function of frequency alone. At higher degrees, the inclination of the acoustic ray paths from the normal to the reflecting layers becomes significant, and gives rise to a degree dependence. With the current accuracy of frequency measurements, this phenomenon is significant for all the p modes trapped in the convection zone. We describe a technique capable of separating the degreedependent component from the leading term a0(cd). We determine the leading-order contribution to the degree dependence of a from the solar p-mode frequencies reported by Libbrecht, Woodard & Kaufman, and compare the results with direct computations from a solar model based on the formalism described by Brodsky & Vorontsov. The dominant contribution comes from the second helium ionization zone, and can be used as a new source of information relevant to the helioseismic calibration of the equation of state of the solar plasma and to the determination of the solar helium abundance.