Beginning in the sixties-seventies of 20th century, extensive studies of powerful high-frequency radio waves interaction with ionospheric plasma has been carried out. This research is of great significance for investigating fundamental processes in the space plasma and for many applications, such as satellite navigation and communication systems, the development of wireless power transfer, etc. In this book we propose and discuss some new precise techniques for the diagnostics of small scale artificially produced plasma irregularities that manifest various linear and nonlinear processes in the region modified by radio waves. The book can be useful for scientists and engineers working in the fields of plasma physics, radar observations, and radio communications.