arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1209.0548astro-ph.SR
收藏

太阳表面速度和磁场的功率谱及其与无符号磁通量密度的关系

Power spectra of velocities and magnetic fields on the solar surface and their dependence on the unsigned magnetic flux density

Y. Katsukawa, D. Orozco Suarez

摘要:

我们已经进行了表面温度,速度和磁场的功率谱分析,使用光谱偏振数据与日出太阳光学望远镜。当我们在超颗粒尺度的视场中制作功率谱时,动力学和热功率谱在颗粒尺度上有一个突出的峰,而磁功率谱在各种空间尺度上有一个广泛分布的功率,在颗粒和超颗粒尺度上都有弱峰。为了分别研究网络间和网络区域的功率谱,在从视场中提取的小的子区域中导出功率谱。我们研究的斜率的功率谱使用幂律指数,并将它们与无符号的磁通量密度平均在子区域。在亚颗粒尺度上,网络间区域的热谱和动力学谱比磁谱陡,幂律指数相差约2。在该尺度下,磁功率谱的幂律指数接近或小于-1,表明总磁能主要来自颗粒尺度磁结构或颗粒尺度和较小尺度磁结构的均匀贡献。随着网络区域中无符号通量密度的增加,热功率谱和动力学功率谱的斜率变得不那么陡峭。当无符号通量密度大于200 Mx cm^-2时,所有热功率谱、动力学功率谱和磁功率谱的幂律指数变得相似。

英文摘要:

We have performed power spectral analysis of surface temperatures, velocities, and magnetic fields, using spectro-polarimetric data taken with the Hinode Solar Optical Telescope. When we make power spectra in a field-of-view covering the super-granular scale, kinetic and thermal power spectra have a prominent peak at the granular scale while the magnetic power spectra have a broadly distributed power over various spatial scales with weak peaks at both the granular and supergranular scales. To study the power spectra separately in internetwork and network regions, power spectra are derived in small sub-regions extracted from the field-of-view. We examine slopes of the power spectra using power-law indices, and compare them with the unsigned magnetic flux density averaged in the sub-regions. The thermal and kinetic spectra are steeper than the magnetic ones at the sub-granular scale in the internetwork regions, and the power-law indices differ by about 2. The power-law indices of the magnetic power spectra are close to or smaller than -1 at that scale, which suggests the total magnetic energy mainly comes from either the granular scale magnetic structures or both the granular scale and smaller ones contributing evenly. The slopes of the thermal and kinetic power spectra become less steep with increasing unsigned flux density in the network regions. The power-law indices of all the thermal, kinetic, and magnetic power spectra become similar when the unsigned flux density is larger than 200 Mx cm^-2.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑