Masers, Lasers and the Interstellar Medium

This paper discusses recent results obtained by myself and my colleagues in three domains of astrophysics: interstellar supersonic turbulence, circumstellar disks, and natural masers and lasers. S.A. Kaplan, S.B. Pikelner, and I.S. Shklovskii were among those who, 30-40 years ago, laid the foundation of these domains.H2O masers become an effective probe of supersonic turbulence associated with mass outflow from very young stars. They demonstrate a very low (1) fractal dimension of the spatial set on which turbulence dissipates its kinetic energy, and, thereby, a strong intermittency of the turbulence. They also indicate that supersonic turbulence, like incompressible turbulence, has an inner scale, on which the bulk of turbulent energy dissipates in low-Mach, random shocks. H2O masers themselves find thereby a new pumping source in these random shocks.Masers in hydrogen recombination lines, discovered 8 years ago, originate in a circumstellar disk surrounding a massive star MWC 349A. They give a possibility to investigate kinematics and structure of the disk. Far-infrared nydrogen recombination lines, recently detected in MWC349A from the Kuiper Airborn Observatory, proved to be amplified as well. They are the first known natural amplifiers of electromagnetic waves in the laser wavelength domain. Analysis of their radiation, along with the radiation in other recombination lines, gives a possible key to understanding the lack of optical lasers in the Universe.