This paper presents two modifications of compressive sensing (CS)-based approach applied to the near-field diagnosis of active phased arrays. CS-based antenna array diagnosis allows a significant reduction of measurement time, which is crucial for the characterization of electrically large active antenna arrays, e.g. used in synthetic aperture radar. However, practical implementation of this method is limited by two factors: first, it is sensitive to thermal instabilities of the array under test, and second, excitation reconstruction accuracy strongly depends on the accuracy of the elements of the measurement matrix. First proposed modification allows taking into account of thermal instability of the array by using an iterative ℓ1-minimization procedure. The second modification increases the accuracy of reconstruction using several simple additional measurements.

The significance of radiative cooling for the stability properties of colliding astrophysical flows is shown. In the cases of WR ring nebula NGC 6888 and WR binary V444 Cyg it is found that thermal instabilities in the radiative loss function A(T) Tβ, β = β(T) not only have an influence on the dynamics of the collision zone, but also that they lead to a quasi-periodic increase of the radiated energy.