论文标题
复杂的冠状血浆中的相混合和波加热
Phase mixing and wave heating in a complex coronal plasma
论文作者
论文摘要
目标。我们通过在复杂的磁场中的反向传播，混合的阿尔氏波的非线性相互作用来研究小尺度的形成和MHD波能的耗散。方法。我们对复杂磁场中的横波进行了完全3-D，非理想的MHD模拟。连续波动驱动器被施加在磁场线的脚步点上，并将系统进化为几个Alfven行进时间。允许相结合的波反射到上边界，并分析了所得反式波数据包之间的相互作用。结果。背景磁场的复杂性质鼓励相混合的发展，从而导致电流和涡度的增长。反向传输的相结合波会诱导一系列能量，并导致更有效的能量耗散。在具有更复杂磁场的模拟中，这种效果得到了增强。高频驱动器激发了局部野外线共振并产生有效的波浪加热。但是，这取决于在共振场线上形成大幅度振荡。频率较小的驱动器比田间线的基本频率无法激发共振，因此不能为冠状加热注入足够的po循环。即使在高频振荡的情况下，即使在安静的太阳下，耗散速度也可能太慢，无法平衡冠状能量损失。结论。对于此处介绍的广义相结合，复杂的背景场结构增强了波能耗散的速率。但是，逼真的波浪驱动器仍然很难注入足够的po液助理以加热电晕。实际上，仅在表现出比太阳大气中观察到的幅度大得多的情况下发生明显的加热。
Aims. We investigate the formation of small scales and the dissipation of MHD wave energy through non-linear interactions of counter-propagating, phase-mixed Alfvenic waves in a complex magnetic field. Methods. We conducted fully 3-D, non-ideal MHD simulations of transverse waves in complex magnetic fields. Continuous wave drivers were imposed on the foot points of magnetic field lines and the system was evolved for several Alfven travel times. Phase-mixed waves were allowed to reflect off the upper boundary and the interactions between the resultant counter-streaming wave packets were analysed. Results. The complex nature of the background magnetic field encourages the development of phase mixing, leading to a growth in currents and vorticities. Counter-propagating phase-mixed waves induce a cascade of energy to small scales and result in more efficient energy dissipation. This effect is enhanced in simulations with more complex magnetic fields. High-frequency drivers excite localised field line resonances and produce efficient wave heating. However, this relies on the formation of large amplitude oscillations on resonant field lines. Drivers with smaller frequencies than the fundamental frequencies of field lines are not able to excite resonances and thus do not inject sufficient Poynting flux to power coronal heating. Even in the case of high-frequency oscillations, the rate of dissipation is likely too slow to balance coronal energy losses, even within the quiet Sun. Conclusions. For the generalised phase-mixing presented here, complex background field structures enhance the rate of wave energy dissipation. However, it remains difficult for realistic wave drivers to inject sufficient Poynting flux to heat the corona. Indeed, significant heating only occurs in cases which exhibit amplitudes that are much larger than those currently observed in the solar atmosphere.
