赤道电离层泡短波区密度谱理论分析

THEORY OF THE PLASMA BUBBLE'S SHORT WAVELENGTH WAVE NUMBER SPECTRUM AT EQUATORIAL IONOSPHERE

本文主要讨论在导致赤道夜间扩展F回波的上升汽泡中,短波区(λ25m)等离子体密度谱分布的物理机制,说明不均匀体内不同的湍动水平将产生不同的谱结构。对于较低湍动水平的汽泡,由于纵向离子声波和具有有限平行波矢漂移波的耦合共振相互作用,导致波模间能量的有效传输,从而控制湍动水平的发展,形成等能多峰谱结构。另一方面,对于湍动充分发展的汽泡,由长波区大幅度扰动维持的短波区强漂移湍动态,在Kr_(Li)≈2处形成一较宽的极大谱峰,然后谱以K^(-2.6)的形式减小。理论分析和探测结果符合甚好。

In this paper, the short wavelength domain power spectra of plsama bubbles has been discussed. For developing bubbles, it is the interactions of drift waves at finite parallel wavelength with ion-acoustic waves that leads to the energy transference among the drift modes, and controls the turbulent level of the coupled system showing equal power multiple peaks spectral structure. Whereas, for well-developed more time delayed bubbles, it is found that long-wavelength large amplitude pertibations can generate the strong drift wave turbulent state in short wavelength domain, causing k-2.6 power spectra, and transfer energy toward increasing k.