Sound amplification by stimulated emission of radiation phenomenon, known as the Larsen effect, is the result of a positive feedback. In general, every oscillator consists of three main parts. These are the power source or pump, the amplifier and the positive feedback leading to the output. The corresponding parts in a SASER device are the excitation or pumping mechanism, the active (amplifying) medium, and the feedback leading to acoustic radiation. Pumping can be performed, for instance, with an alternating electric field or with some mechanical vibrations of resonators. The active medium should be a material in which sound amplification can be induced. An example of a feedback
A-235 anti-ballistic missile system A-235 and the A-135 missile defense system [6]. According to foreign media reports, on November 18, 2015, the first successful launch of the Nudol missile and the third launch in the missile test program of the complex took place. Presumably, the deployment site of the A-235 missile defense system will be the former base area of the A-135 missile defense system near Moscow. According to the plan, the complex will have the capabilities to intercept the warheads of ballistic missiles, as well as spacecraft [4]. In May 2016, system elements were tested as part of the exercises of the Military