Forward Modeling of Simulated Transverse Oscillations in Coronal Loops and the Influence of Background Emission
Forward Modeling of Simulated Transverse Oscillations in Coronal Loops and the Influence of Background Emission
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冠状环中模拟横向振荡的正演建模以及背景发射的影响
DOI：
10.3847/1538-4357/ac2497
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发表时间：
2021-09
期刊：
影响因子：
--
通讯作者：
Li Bo
中科院分区：
文献类型：
--
作者：
Shi Mijie;Van Doorsselaere Tom;Antolin Patrick;Li Bo
我们模拟了辐射冷却日冕环的横向振荡，并对它们的光谱和成像特征进行了正演模拟，注意了背景辐射的影响。横向振荡由周期性速度驱动器在一个足点处驱动。随后形成一个扭结驻波，由于Kelvin-Helmholtz不稳定性，环路横截面发生变形，导致能量耗散和小尺度加热。除了横向运动，长周期的纵向流动也产生由于有质动力引起的慢波。然后，我们将模拟的直环转换为半环面环，并对它们的光谱仪和成像发射进行前向建模，模仿Hinode/EIS和SDO/AIA的观测。我们发现，在不同的狭缝位置，强度的振荡幅度是不同的，但在不同的谱线或通道大致相同。多普勒速度和多普勒宽度的X-t图均显示周期性信号。我们还发现，背景发射显着降低多普勒速度，使估计的动能两个数量级小于真实的值。我们的研究结果表明，背景扣除可以帮助恢复真实的振荡速度。这些结果有助于进一步认识冕环中的横向振荡及其观测特征。然而，他们对使用多普勒速度在光谱上估计横波的能量含量表示怀疑。
We simulate transverse oscillations in radiatively cooling coronal loops and forward-model their spectroscopic and imaging signatures, paying attention to the influence of background emission. The transverse oscillations are driven at one footpoint by a periodic velocity driver. A standing kink wave is subsequently formed and the loop cross section is deformed due to the Kelvin–Helmholtz instability, resulting in energy dissipation and heating at small scales. Besides the transverse motions, a long-period longitudinal flow is also generated due to the ponderomotive force induced slow wave. We then transform the simulated straight loop to a semi-torus loop and forward-model their spectrometer and imaging emissions, mimicking observations of Hinode/EIS and SDO/AIA. We find that the oscillation amplitudes of the intensity are different at different slit positions, but are roughly the same in different spectral lines or channels. X-t diagrams of both the Doppler velocity and the Doppler width show periodic signals. We also find that the background emission dramatically decreases the Doppler velocity, making the estimated kinetic energy two orders of magnitude smaller than the real value. Our results show that background subtraction can help recover the real oscillation velocity. These results are helpful for further understanding transverse oscillations in coronal loops and their observational signatures. However, they cast doubt on the spectroscopically estimated energy content of transverse waves using the Doppler velocity.
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DOI：
10.1086/593203
发表时间：
2008-09
期刊：
The Astrophysical Journal Letters
影响因子：
--
作者：
J. Terradas;J. Andries;J. Andries;Marcel Goossens;I. Arregui;R. Oliver;J. Ballester
通讯作者：
J. Terradas;J. Andries;J. Andries;Marcel Goossens;I. Arregui;R. Oliver;J. Ballester
DOI：
10.1051/0004-6361/201730598
发表时间：
2017-06
期刊：
arXiv: Solar and Stellar Astrophysics
影响因子：
--
作者：
K. Karampelas;T. Doorsselaere;P. Antolin
通讯作者：
K. Karampelas;T. Doorsselaere;P. Antolin
影响因子：
4.9
作者：
Guo Mingzhe;Van Doorsselaere Tom;Karampelas Konstantinos;Li Bo
通讯作者：
Li Bo
影响因子：
6.5
作者：
G. Nisticò;V. Nakariakov;E. Verwichte
通讯作者：
G. Nisticò;V. Nakariakov;E. Verwichte
影响因子：
6.5
作者：
D. Pascoe;A. Hood;I. Moortel;A. Wright
通讯作者：
D. Pascoe;A. Hood;I. Moortel;A. Wright