Mode conversion of radiatively damped magnetogravity waves in the solar chromosphere
Mode conversion of radiatively damped magnetogravity waves in the solar chromosphere
复制标题
太阳色球层辐射阻尼磁重力波的模式转换
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
P. Cally
中科院分区：
文献类型：
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作者：
M. Newington;P. Cally
对太阳大气中绝热重力波传播的模拟表明，在高度倾斜的磁场存在下，模式转换为场引导声波或阿尔芬波是可能的。本工作旨在扩展以往的绝热研究，探讨辐射阻尼对太阳大气中重力波传播和模态转换的影响。我们在VAL-C大气中模拟重力波，受到均匀的，任意方向的磁场，使用牛顿冷却近似辐射阻尼传播。结果表明，在存在阻尼的情况下，绝热研究中确定的模态转换路径仍然保持不变。波能通量对辐射阻尼时间的高度依赖形式非常敏感。虽然与绝热结果相比，从0.2 Mm开始的模拟导致了适度的通量衰减，但从光球底部开始的模拟中，低光球预期的短阻尼时间有效地抑制了重力波。我们的结果很难与在光球高度传播具有显著能量通量的重力波的观测相一致，除非它们是在原位产生的。
Modelling of adiabatic gravity wave propagation in the solar atmosphere showed that mode conversion to field guided acoustic waves or Alfven waves was possible in the presence of highly inclined magnetic fields. This work aims to extend the previous adiabatic study, exploring the consequences of radiative damping on the propagation and mode conversion of gravity waves in the solar atmosphere. We model gravity waves in a VAL-C atmosphere, subject to a uniform, and arbitrarily orientated magnetic field, using the Newton cooling approximation for radiatively damped propagation. The results indicate that the mode conversion pathways identified in the adiabatic study are maintained in the presence of damping. The wave energy fluxes are highly sensitive to the form of the height dependence of the radiative damping time. While simulations starting from 0.2 Mm result in modest flux attenuation compared to the adiabatic results, short damping times expected in the low photosphere effectively suppress gravity waves in simulations starting at the base of the photosphere. It is difficult to reconcile our results and observations of propagating gravity waves with significant energy flux at photospheric heights unless they are generated in situ.