Wave-Wave Interaction in Astrophysical Shocks and the Interstellar Medium

天体物理冲击附近的湍流通常由MHD波组成。单波模级联模型忽略了不同波模之间的相互作用。然而，Vainio & Spanier（2005）能够证明波型相互作用可以显著改变湍流的性质。然而，目前还没有一个完整的MHD波模拟湍流的模型。因此，我建议建立一个数值模型，其中三个主要部分用于描述湍流级联：首先是波能在一个波模内的级联，然后是波波相互作用在波模之间的能量传递，最后是波阻尼对这些级联的影响。这个模型适用于激波锋面产生的波状湍流，在那里MHD波被认为是宇宙射线加速的原因。该模型的结果也适用于星际介质，它可以澄清湍流的性质。

Turbulence in the vicinity of astrophysical shocks is usually to be composed of MHD waves. Models for the cascade of one wavemode is neglect, interactions between different wavemodes. Vainio & Spanier (2005) however were able to show that wavemode interactions can change the properties of turbulence significantly. Still a complete model of turbulence modelled by MHD waves is not at hand. I therefore suggest to develop a numerical model in which three major components are used to describe the turbulent cascade: First of all the cascading of wave energy within one wavemode, then the energy transfer between wavemodes by wave wave interactions and finally the influence of wave damping on these cascades. This model is applicable to the generation of wave-like turbulence at shockfronts, where MHD waves are thought to be responsible for the acceleration of Cosmic Rays. The results of this model are also applicable for the interstellar medium where it can clarify the nature of turbulence.