Transmission and conversion of magnetoacoustic waves on the magnetic canopy in a quiet Sun region
Transmission and conversion of magnetoacoustic waves on the magnetic canopy in a quiet Sun region
复制标题
安静太阳区域磁冠上磁声波的传输和转换
DOI：
10.1051/0004-6361/201423986
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发表时间：
2014
影响因子：
6.5
通讯作者：
K. Tziotziou
中科院分区：
文献类型：
--
作者：
I. Kontogiannis;G. Tsiropoula;K. Tziotziou
我们提出的证据的转换和传输的磁通量管，构成斑驳和形成的磁冠在一个安静的太阳区域的波模式，突出的细节和关键参数的机制，在H{\alpha}中观察到的磁网络产生功率晕和磁阴影。我们使用磁场矢量和磁罩高度的计算和简单的假设来确定转弯高度，即，快速磁声波反射的高度。我们比较了磁阴影和功率晕中声功率的变化与模式转换和传输的二维模型的结果。模型的关键参数是攻角，攻角与磁场矢量在冠层高度的倾角有关。我们的分析还考虑到：1）波的传播存在投影效应; 2）磁冠和转向高度是弯曲层; 3）周期大于3 min的波在倾斜磁场存在下到达色球层（斜坡效应），4）斑点是冠状结构，5）H{\alpha}的翅膀包含来自低和高{\beta}等离子体的混合信号。功率对攻角的依赖关系很好地遵循了二维模型的预期。长周期慢波沿着斑点的磁场线被引导到色球上层，而短周期快波则穿透磁冠并在转向高度反射。虽然这两种磁声模式有助于速度信号，使观测的解释是一项具有挑战性的任务，我们得出结论，转换和传输的声波到快速和慢速磁声波是负责形成功率晕和磁阴影在安静的太阳区域。
We present evidence for the conversion and transmission of wave modes on the magnetic flux tubes that constitute mottles and form the magnetic canopy in a quiet Sun region, highlighting the details and key parameters of the mechanism that produces power halos and magnetic shadows at the magnetic network observed in H{\alpha}. We use calculations of the magnetic field vector and the height of the magnetic canopy and simple assumptions to determine the turning height, i.e., the height at which the fast magneto-acoustic waves reflect. We compare the variation of acoustic power in the magnetic shadow and the power halo with the results of a two-dimensional model on mode conversion and transmission. The key parameter of the model is the attack angle, which is related to the inclination of the magnetic field vector at the canopy height. Our analysis takes also into account that 1) there are projection effects on the propagation of waves, 2) the magnetic canopy and the turning height are curved layers, 3) waves with periods longer than 3 min reach the chromosphere in the presence of inclined magnetic fields (ramp effect), 4) mottles are canopy structures, and 5) the wings of H{\alpha} contain mixed signal from low- and high-{\beta} plasma. The dependence of power on the attack angle follows the anticipated by the two-dimensional model very well. Long-period slow waves are channeled to the upper chromospheric layers following the magnetic field lines of mottles, while short-period fast waves penetrate the magnetic canopy and reflect at the turning height. Although both magnetoacoustic modes contribute to velocity signals, making the interpretation of observations a challenging task, we conclude that conversion and transmission of the acoustic waves into fast and slow magnetoacoustic waves are responsible for forming power halos and magnetic shadows in the quiet Sun region.
DOI：
10.1088/2041-8205/744/1/l5
发表时间：
2011-11
期刊：
The Astrophysical Journal Letters
影响因子：
--
作者：
D. Jess;D. Pascoe;D. Christian;M. Mathioudakis;P. Keys;F. Keenan
通讯作者：
D. Jess;D. Pascoe;D. Christian;M. Mathioudakis;P. Keys;F. Keenan