标题： 太阳内部氢配分函数的helioseismic分析 显示英文标题

标题： Helioseismic analysis of the hydrogen partition function in the solar interior

摘要： 分析了倒置太阳数据与太阳模型之间的绝热梯度 γ₁ 差异。 为了深入了解等离子体物理学的问题，提取了所谓的“固有” γ₁ 差异，即仅由于状态方程的变化而引起的差异。 我们的方法使用基于两种当前用于太阳建模的状态方程的参考模型，分别是米哈洛斯-汉默-丹彭（MHD）状态方程和劳伦斯利弗莫尔开发的OPAL状态方程。 利用SOHO航天器上SOI/MDI仪器在其运行前144天内的太阳振荡频率数据。 我们的结果证实了之前仅通过理论研究的氢激发态的微妙效应（Nayfonov & Dappen 1998）的存在。 该效应源于米哈洛斯-汉默-丹彭状态方程中使用的氢内部配分函数。 尽管这是一个纯氢效应，但它发生在太阳更深的一些层次中，在这些层次中超过90%的氢被电离，并且位于氦的二次电离区。 因此，在可靠地确定太阳对流区相关的天体物理氦丰度时，必须考虑到这一效应。 显示英文摘要

摘要： The difference in the adiabatic gradient gamma_1 between inverted solar data and solar models is analyzed. To obtain deeper insight into the issues of plasma physics, the so-called ``intrinsic'' difference in gamma_1 is extracted, that is, the difference due to the change in the equation of state alone. Our method uses reference models based on two equations of state currently used in solar modeling, the Mihalas-Hummer-Dappen (MHD) equation of state, and the OPAL equation of state (developed at Livermore). Solar oscillation frequencies from the SOI/MDI instrument on board the SOHO spacecraft during its first 144 days in operation are used. Our results confirm the existence of a subtle effect of the excited states in hydrogen that was previously studied only theoretically (Nayfonov & Dappen 1998). The effect stems from internal partition function of hydrogen, as used in the MHD equation of state. Although it is a pure-hydrogen effect, it takes place in somewhat deeper layers of the Sun, where more than 90% of hydrogen is ionized, and where the second ionization zone of helium is located. Therefore, the effect will have to be taken into account in reliable helioseismic determinations of the astrophysically relevant helium-abundance of the solar convection zone.