Page 39 - Winter2021

P. 39

```
Tatarskii’s MS advisor in the early 1950s at Moscow State
University, Moscow, Russia, and he formulated Valerian’s
thesis topic: sound propagation in a turbulent atmo-
sphere. In 1953, Tatarskii began work under Alexander
Obukhov (a prominent atmospheric physicist and statis-
tician), at what later became the Institute of Atmospheric
Physics, in Moscow. Obukhov asked Tatarskii to apply
the Rytov method to a variety of problems in acoustic and
electromagnetic wave propagation. The powerful results
obtained were summarized in Tatarskii’s PhD disserta- “Wave Propagation in Random Media” held in Tallin,
tion, completed in 1957, and in his first book (1959).
The Rytov method describes weak (unsaturated) fluc- tuations in propagating waves. Motivated by various applications, many scientists subsequently worked on advanced methods for the challenging problem of strong fluctuations. To this end, Tatarskii pioneered the use of diagram techniques (Tatarskii, 1967) and the Markov approximation (Tatarskii, 1969). He also contributed to development of other methods such as parabolic equations, variational derivatives, and the Feynman path integral. These new methods enabled solution of many challenging problems, and many phenomena were explained or discovered, such as the saturation of
Estonia (Figure 1). About three dozen leading Russian and foreign scientists, representing widely ranging spe- cialties, participated. The meeting led to a new journal,
Waves in Random Media (now Waves in Complex and Random Media).
Early papers on WPRM were often qualitative; turbu- lence was represented as circles and waves as bending rays. Tatarskii’s books, on the other hand, rigorously described from first principles the full complexity of turbulent media wave propagation. Tatarskii combined his extensive physics background in several areas with a unique ability to present complicated topics clearly. Many scientists working in the field considered Tatarskii to be a mentor. Steven Clifford, director of the NOAA Wave Propagation Laboratory, held Tatarskii in such high esteem that he recruited him in the early 1990s to work there.
Tatarksii was similarly skilled at mentoring students. After reading his books, many young scientists wanted to study under his guidance. Tatarskii was remarkably proficient at rooting out errors in students’ handwritten
calculations. He advised his students to do the deriva- tions once, put their notes aside, repeat the derivations, and then see whether the results coincide.
When working on his second book, Tatarskii usually wrote about 15 handwritten pages a day. Remarkably, these handwritten pages turned out to be the only draft of the book and read quite clearly! Although Tatarskii used to mention Voltaire’s aphorism “Perfect is the enemy of good,” his books and papers are remarkably close to perfect in their ability to explain complicated problems. Although Tatarskii understood his contributions to the field, he remained humble: “I do not think very fast” and
“There are people in Russian Academy of Sciences who are smarter than me.”
intensity fluctuations and random medium backscat- tering enhancement. These methods and results were summarized in Tatarskii’s second book (1967) and a later book coauthored with Rytov and Kravtsov (Rytov et al., 1989).
From the beginning, WPRM has been an interdisciplin- ary field. To build on this, in 1988, Tatarskii (Russia) and Ishimaru (United States) organized the first meeting on
Figure 1. Participants of the First Meeting on Wave Propagation in Random Media, Tallin, Estonia, 1988. From left: first row: Yu. Kravtsov, Mrs. Tatarskaya, V. Tatarskii, Ü. Mullamaa (local host), A. Ishimaru, Mrs. Lang, A. Orekhova (interpreter), Mrs. Flatté, V. Varadan, S. Flatté, A. Gurvich; second row: V. Vorob’ev, V. Shishov, M. Nieto-Vesperinas, R. Hill, R. Lang, I. Besieris, Y. Kuga; third row: Yu. Barabanenkov, I. Yakushkin, A. Saichev, V. Freilikher, V. Brekhovskikh, E. Bakhar, Mrs. Bakhar, L. Tsang, K. Yeh, V. Klyatskin; fourth row: I. Granberg (organizing committee), C. Rino, G. Brown, V. Zavorotny, V. Ostashev, J. Dainty, V. Sekistov.
Winter 2021 • Acoustics Today 39
```