RAPID FLUCTUATIONS IN THE LOWER SOLAR ATMOSPHERE
RAPID FLUCTUATIONS IN THE LOWER SOLAR ATMOSPHERE
复制标题
太阳系低层大气的快速波动
DOI：
--
复制
发表时间：
2011
期刊：
影响因子：
--
通讯作者：
M. Mathioudakis
中科院分区：
文献类型：
--
作者：
J. Lawrence;A. Cadavid;D. Christian;D. Jess;M. Mathioudakis
太阳大气仪器中的快速振荡揭示了太阳大气高频波动。G带强度(IG)和Ca II K线强度(IK)的变化频谱分别显示在白噪声以上到300兆赫兹和50兆赫兹以上的相关波动。经噪声校正的f=28-326 MHz的G带频谱呈现指数−为1.2 1±0.0 2的幂规律，与湍流运动的存在相一致。在25-100 MHz(“UHF”)范围内的G波段光谱功率集中在晶间通道中的磁亮点位置，并且在时间上具有高度间歇性。正峰度κ显示的超高频G波段波动的间歇性也表明存在湍流。组合IG、IK、超高频功率和κ的值可以显示太阳大气的两种截然不同的状态。状态1包括几乎所有的数据，具有低IG、IK、UHF功率和κ≈6的特征。状态2只包括很小一部分数据，具有高IG、IK、UHF功率和κ≈3的特征。叠加历元分析表明，在任一状态下，超高频功率峰值与时空IG极大值同时出现。对于状态1，IK显示了3.5分钟的色球振荡，最大值出现在IG极大值之后的21 S，这意味着有效高度差150-210公里。然而，对于状态2，Ik和Ig最大值是同时的；在这种高度磁化的环境中，G带和K线发射的位置在空间上可能是接近的。
The Rapid Oscillations in the Solar Atmosphere instrument reveals solar atmospheric fluctuations at high frequencies. Spectra of variations of the G-band intensity (IG) and Ca ii K-line intensity (IK) show correlated fluctuations above white noise to frequencies beyond 300 mHz and 50 mHz, respectively. The noise-corrected G-band spectrum for f = 28–326 mHz shows a power law with exponent −1.21 ± 0.02, consistent with the presence of turbulent motions. G-band spectral power in the 25–100 mHz (“UHF”) range is concentrated at the locations of magnetic bright points in the intergranular lanes and is highly intermittent in time. The intermittence of the UHF G-band fluctuations, shown by a positive kurtosis κ, also suggests turbulence. Combining values of IG, IK, UHF power, and κ reveals two distinct states of the solar atmosphere. State 1, including almost all the data, is characterized by low IG, IK, and UHF power and κ ≈ 6. State 2, including only a very small fraction of the data, is characterized by high IG, IK, and UHF power and κ ≈ 3. Superposed epoch analysis shows that the UHF power peaks simultaneously with spatio-temporal IG maxima in either state. For State 1, IK shows 3.5 minute chromospheric oscillations with maxima occurring 21 s after IG maxima implying a 150–210 km effective height difference. However, for State 2 the IK and IG maxima are simultaneous; in this highly magnetized environment sites of G-band and K-line emission may be spatially close together.