Diagnostics of electromagnetic waves in the vacuum

Under interaction of plasma flows there are electromagnetic waves are generated in the plasma. They can be distributed in different directions, interact with the plasma and can be changed by amplitude and motion direction. The study of the generating electromagnetic waves in the plasma is impossible due to the nonlinear character of such interaction when modeling. In many problems to solve this problem one places a vacuum domain next to the plasma region, where the generated by the plasma electromagnetic waves are studied. Waves in vacuum follow to the linear Maxwell equations and, therefore, it is easy to determine their frequencies and amplitudes using the Fourier analysis. To study this matter, it is sufficient to consider the problem in the 2D case. The aim of the current work is the development of the technique to determine directions and amplitudes of all electromagnetic waves in the vacuum which are present in a computational domain at definite time. (paper)