论文标题
来自不均匀等离子体的磁性水力学波的巨大过度反射，剪切流不均匀
Giant overreflection of magnetohydrodynamic waves from inhomogeneous plasmas with nonuniform shear flows
论文作者
论文摘要
我们使用基于不均匀的剪切流动流，使用基于不均匀的透射系数的精确数值计算，基于不均匀的剪切计算，基于不均匀的剪切流，我们研究了不均匀平面分离的等离子体中磁氢动力波的共振过度反射。流速和外部磁场垂直于不均匀性方向以及流速和血浆密度沿其任意差异。当有剪切流量时，波频频率将通过多普勒移位和谐振放大和过反射在局部调节，而调制频率为负，并且其绝对值与本地alfvén或缓慢的频率匹配。对于许多不同类型的密度和流速度曲线，我们发现，尤其是当参数是完全反射的，当入射波完全反射时，会产生巨大的过度反射，在该反射率中，反射率在相当广泛的入射角度，频率，等离子$β$及其最大值的最大值及其最大值的值大于10^5^5^5^5^5^5 $ $ 10中的频率大于10。在有限的$β$等离子体中，发现快速和缓慢的磁波波会导致强烈反射，并且在等离子体内表现出多个位置表现出Alfvén和缓慢的共振。我们解释了过度反转的机制，即由于在那里的半结合状态而导致的不均匀和开放空腔的形成，并且在谐振和共振的距离上的强烈增强。我们对磁化陆地和太阳等离子体的观察后果进行讨论。
We study theoretically mode conversion and resonant overreflection of magnetohydrodynamic waves in an inhomogeneous plane-stratified plasma in the presence of a nonuniform shear flow, using precise numerical calculations of the reflection and transmission coefficients and the field distributions based on the invariant imbedding method. The cases where the flow velocity and the external magnetic field are directed perpendicularly to the inhomogeneity direction and both the flow velocity and the plasma density vary arbitrarily along it are considered. When there is a shear flow, the wave frequency is modulated locally by the Doppler shift and resonant amplification and overreflection occur where the modulated frequency is negative and its absolute value matches the local Alfvén or slow frequency. For many different types of the density and flow velocity profiles, we find that, especially when the parameters are such that the incident waves are totally reflected, there arises a giant overreflection where the reflectance is much larger than 10 in a fairly broad range of the incident angles, the frequency, and the plasma $β$ and its maximum attains values larger than $10^5$. In a finite $β$ plasma, both incident fast and slow magnetosonic waves are found to cause strong overreflection and there appear multiple positions exhibiting both Alfvén and slow resonances inside the plasma. We explain the mechanism of overreflection in terms of the formation of inhomogeneous and open cavities close to the resonances and the strong enhancement of the wave energy due to the occurrence of semi-bound states there. We give discussions of the observational consequences in magnetized terrestrial and solar plasmas.
