在雷电电磁场的理论计算方面，提出了两种方法，即时域中的偶极子方法和频域中的时变场方法。

About theoretic calculation for lightning electromagnetic field, two analytical methods are raised, which are dipole method in time domain and time-varying field method in frequency domain.

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利用远场时变散斑空-时强度相关函致的有限差商可以测量散射体运动的二维速度矢量。

By using backward difference of space-time intensity correlation function with respect to time delay, the two-dimensional velocity vector of a moving diffuser can be measured.

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引入了时变方向场的概念，用定性方法建立了稳定及不稳的定理。

We introduce the concept of time-variable directional field, and establish the stable and unstable theorems by the qualitative method.

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