Academician L.M. Brekhovskikh: Man and Scientist

N. A. Dubrovskii

Andreev Acoustics Institute. Russian Academv of Sciences.
ul. Shvernika 4, Moscow, 117036 Russia
Received April 10, 1999

In March 1999 in Berlin, the Second Convent of the European Acoustics Association combined with the 137th Session of the Acoustical Society of America was held. At this Convent, the prominent acoustician Academician L.M. Brekhovskikh was given the title of Honored Member of the Acoustical Society of America ".... for the pioneering works on the propagation and scattering of waves." Academician Brekhovskikh has become the 15th Honored member of this society since the day of its foundation in 1929, the list ofhonorees of the Society being headed by Thomas Edison.

Two sessions of the section of Underwater Acoustics were devoted to Academician Brekhovskikh. The subjects discussed at these sessions were his contribution to science, his influence on the development of acoustics and hydroacoustics, and also the personal qualities which allowed him to obtain such impressive results. The lectures were given by the well-known acousticians and oceanologists: W. Munk (USA), Guan' Din'khua (China), 0. Godin (Canada), W. Kuperman (USA), F. Jensen (Saclant Center). Yu. Lysanov (Russia), and others.

My lecture was entitled "Leonid Brekhovskikh: Person and Scientist." The essentials of this lecture are given below, which may be of interest for Russian readers, since few Russian scientists were able to attend the Convent.

The outstanding achievements of Academician Brekhovskikh in science, its development and its popularization are well known. He is the author of important discoveries in acoustics (the discovery of the underwater sound channel) and oceanology (the discovery of synoptic vortices in the ocean along with the fact that they contain up to 90% of its kinetic energy). The books written by Brekhovskikh. alone or together with his colleagues and students (Yu.P. Lysanov, V.V. Goncharov, and O.A. Godin), and, especially, his famous monograph Waves in Layered Media became manuals for several generations of specialists in underwater acoustics. Brekhovskikh is one of the founders of the Andreev Acoustics Institute, the leader of a large scientific school, and a well known professor. For more than 20 famous monograph Waves in Layered Media became manuals for several generations of specialists in underwater acoustics. Brekhovskikh is one of the founders of the Andreev Acoustics Institute, the leader of a large scientific school, and a well-known professor. For more than 20 years, he chaired the Acoustics department (the department of the Hydrocosmos Physics) at the Moscow Physicotechnical Institute.

One can definitely say that Brekhovskikh is a phenomenon. This phenomenon is primarily based on his personal qualities; however, it is also closely related to the favorable conditions of his life that allowed him to realize his creative potential.

Let us consider these personal qualities and the favorable conditions of Brekhovskikh's life.

First, Brekhovskikh is a curious person with an inquiring mind. This quality is considered highly important by Brekhovskikh himself. It was already characteristic of him when he was a little boy and lived in the village, Strunkino. in the Arkhangel'sk region. Brekhovskikh recounted that in the fifth grade he was not allowed to go to school (which was 10 km away from Strunkino) because his parents refused to enter the kolkhoz. As a result, the boy had to stay at home for a whole year. He found a German textbook somewhere, and in one winter, he learned this textbook by heart. In his village, no one knew German; moreover, no one was even literate. Brekhovskikh had to learn first the German letters and then the spelling of German words.

Brekhovskikh is a talented person, and his talent is oriented to a profound analysis of every subject concerned with his work. This personal quality of Brekhovskikh is evident, however I will illustrate it with an example. It is common knowledge that, in the first months of war in 1941, the Germans used underwater mines with acoustic detonators against Russian ships. The navy commanders were looking for the ways to neutralize this new weapon. The Acoustical laboratory of the Physical Institute of the Academy of Sciences of the USSR started working on the development ofhydroacoustic trawls. The Head of the laboratory, N.N. Andreev, formed a group of researchers to be sent to the fleet. Brekhovskikh was included in this group. It was necessary to develop as fast as possible a system that would imitate the acoustic noise of Russian warships.

Fig. 1. N.N. Andreev, L.M. Brekhovskikh. L.D. Rozenberg, (sitting, from left to right: nos. 5, 3, and 4. respectively) and other participants of the development of acoustic trawls in Poti (1942).
The simplest way to solve this problem was to apply the empirical trial-and-error method for selecting a suitable simulator. However, Brekhovskikh decided to perform a complete scientific analysis of the problem. He began with the theoretical analysis of the vibrations of the plates that form the plating of a ship. The calculations allowed him to select the plates and the ways of their fastening and excitation, and to design the first hydroacoustic trawl imitating the noise of vessels. Within four months, the fleet obtained the pilot model of a hydroacoustic trawl. This model was successfully tested in full-scale conditions, and acoustic trawls became an efficient means for ship protection.

While studying the efficiency of acoustic trawls at different distances from the trawling ship, Brekhovskikh encountered the problem of sound propagation in the sea with allowance for the bottom and surface effects. This problem had been little studied before. Brekhovskikh solved it, and since then, the problems of propagation and scattering of waves of different origin became the main subject of his studies.

Brekhovskikh is a creative person. Once, he said that the desire to invent and develop something new was his physical necessity, and if he had not become a scientists, he would have been a writer. His talent in writing clearly manifested itself in his scientific and popular-scientific works.

An important feature of Brekhovskikh is his determination in reaching his goals, the principal one of which was creative work in fundamental science. Brekhovskikh was never concerned ab-out obtaining some temporary practical results. He always followed the principle that there is nothing more practical than fundamental science. In keeping with this principle, he quit the position of the Director of the Acoustics Institute after the institute ceased being subordinate to the Acade-my of Sciences and was placed under the authori-ty of an industrial ministry (this occurred in 1962).

Brekhovskikh's characteristic feature closely related to that mentioned above is his ability to establish priorities in his work and act strictly according to these priorities within given periods of his life. This feature proved to be especially important when Brekhovskikh simultaneously filled a great number of positions at different institutions: the Acoustics Institute; the Division of Oceanology, Physics of Atmosphere, and Geography of the Academy of Sciences; the Moscow Physicotechnical Institute; and some international organizations.

Here, we approach one more feature of Brekhovskikh: the ability to attract talented people be they students, researchers, or administrators. It is difficult to understand how one person could accomplish the duties of the director of a research institute as large as the Acoustics Institute of late 1950s-early 1960s and simultaneously write the book Waves in Layered Media that soon became a "bible" for acousticians. The administrative team formed by Brekhovskikh in 1954-1956 (V.M. Golubkov, F.I. Kryazhev, and M.I. Danilov) was one of the most effective teams in the history of the Acoustics Institute.

Fig. 2. L.M. Brekhovskikh (teacher) and Guan' Din'khua (student) (photograph taken by Dubrovskii in 1999).

Brekhovskikh invited many talented young physicists and engineers to work with him at his laboratory of Acoustic Methods of Ocean Studies. These young people formed the basis of his scientific school: N.S. Ageeva, I.B. Andreeva, O.P. Galkin, Yu.Yu. Zhitkovskii, B.F. Kur'yanov, I.E. Mikhal'tsev, A.V. Furduev, S.D. Chuprov, R.F. Shvachko, and others. Some of them became co-authors of the well-known manual Ocean Acoustics for which Brekhovskikh with co-authors received the State Award in 1976.

Today, the former students of Brekhovskikh can be found not only in Russia and the countries of the former Soviet Union, but also in China, the United States, Canada, and elsewhere. His scientific achievements have become the property of the world scientific community.

A unique feature of Brekhovskikh is his persistence in pursuing his aims. This can be illustrated by his study of yoga. In 1970s, hatha-yoga was quite popular in Moscow. I was one of those who studied this system, and I helped Brekhovskikh to become familiar with the intricate yoga exercises. We often discussed our progress and shared our experiences. At the beginning, Brekhovskikh's joints and spine (who was in his sixties at that time) were not very flexible, but he worked hard, and within a year, he made great progress. The effect of the exercises was astonishing. Brekhovskikh became as full of energy as a young man, and he recovered the creative abilities of his youth. Being persistent and methodical in his yoga practice, he developed his own system of exercises that best suited his own abilities and preferences. Soon, my advice became unnecessary, and the system worked out by Brekhovskikh allowed him to retain his health and creative abilities for years.

It should be noted that Brekhovskikh had always practiced regular exercises to remain fit and healthy.

A specific feature of Brekhovskikh is his restraint, which manifests itself in both speech and written works. He is (as is usually said in England) a man of few words. His speech is slow but informative. Brekhovskikh always attracts the attention of the audience.

From his parents, Brekhovskikh inherited the natural wisdom that allows him to encounter both good and bad events with patience and composure. A sense of humor helps him to overcome the difficulties that have occurred in his life. In 1942, Brekhovskikh and his wife Lidiya came to Moscow after several months of hard work on the development of acoustic trawls. In Moscow, they had no apartment to live in, and they had to share a room with a group of colleagues at a hostel. His family's privacy was protected by a curtain that separated the family part of the room from the bachelor one. Later, Brekhovskikh's family moved to a small room in the "Small Acoustics" building on the territory of the Physical Institute of the Academy of Sciences where, at that time, the Acoustics laboratory was located. In 1953 on the basis of this laboratory, the Acoustics Institute was established, and Brekhovskikh became its first director.

Later, describing his life, Brekhovskikh demonstrated a humorous attitude toward his housing problems. For him, the main thing was the possibility for creative work, and such a possibility existed even in those awful living conditions.

Now, let us consider the circumstances that were favorable to the realization of Brekhovskikh as a person and a scientist. These circumstances are complicated and determined by both people surrounding Brekhovskikh and the historic conditions and events in Russia.

First of all, it is necessary to outline the role of the parents of Brekhovskikh and, especially, the role of his mother. Being an illiterate woman, she noticed the creative abilities of her little son—one of her seven children. Although he was only thirteen years old and looked small and thin, she allowed him to go to live with his brother in Krasnoural'sk, where he could study at school.

The parents gave "creative genes" to their children: of the six Brekhovskikh brothers, four became top-level professionals. The oldest brother, Feodosii, became a metallurgical engineer, a winner of the State Award. Serafim became a doctor of science and a well-known specialist in high-strength glass technology. He organized the Institute of Technical Glass in Moscow. This institute produced bullet-proof glass for airplanes and tanks. Nikolai joined the army; he graduated from an Artillery school and was a regiment commander during the war. In the following years, he worked as an editor of the Artillery Journal. Aleksandr studied at the Perm' University and became a physicist. He specialized in the physical properties of metals.

The second important circumstance is that Brekhovskikh was born at the proper time. Before the outbreak of war in Russia in 1941, he had already completed his candidate dissertation and become an important figure at the Acoustical laboratory. N.N. Andreev noticed his talent and, at the beginning of the war, included him in the team that worked on the development of trawls for protecting ships from acoustic mines. Owing to this work, Brekhovskikh did not fight at the front and was not killed, the way millions of young Russian soldiers were. Had he been born a couple of years later, the circumstances could have been different.

The creative period of Brekhovskikh's life coincided with the "golden age" of Soviet science. Huge financial and human resources of the country were invested in the development of fundamental and applied studies and the development of military technologies. Ocean acoustics was given an impetus by the establishment of the Acoustics Institute in 1953. Additional important factors were the construction of unique research ships Sergei Vavilov and Petr Lebedev and the appearance of top-level young specialists from the Moscow Physicotechnical Institute at the Acoustics Institute. Brekhovskikh became the first director of the Acoustics Institute, he organized the laboratory of Acoustic Methods of Ocean Studies and carried out numerous expeditions on research ships to different regions of the ocean. These expeditions made it possible to verify his previously developed theory in full-scale conditions.

Brekhovskikh was lucky to encounter many outstanding scientists and talented young people who became his teachers, friends, colleagues, and students. Brekhovskikh distinguished between two groups of his teachers. One group consisted of young theoreticians of the Perm' University, namely, Stepanov and Bazilevskaya, who were considered by Brekhovskikh as his tme teachers. "They did not fill the vessel, but kindled the torch," said Brekhovskikh about them. They awakened the interest to creative work in science among their students. Their lectures often turned into hot discussions between students and professors.

The second group of teachers was represented by the famous physicists: Academician M.A. Leontovich (he supervised Brekhovskikh's work on his candidate dissertation). Academician I.E. Tamm, and Academician N.N. Andreev. These scientists being much older than Brekhovskikh taught him to be a real scientist and a citizen of his country, but they did not go into the heart of his research. Brekhovskikh became a self-educated postgraduate student and, later, an independent young researcher. Without anyone's help, he selected the subject of his candidate dissertation: Theory of X-ray Scattering in Crystals.

Brekhovskikh counted many interesting people among his friends. One of his best friends was Academician A.M. Prokhorov—a Nobel Prize laureate and the first Director of the General Physics Institute of the Russian Academy of Sciences.

Part of Brekhovskikh's success should be attributed to his wife Lidiya. She gave him support and adviceahd shared with him the difficulties during the time of war and after it. She took care of their three children— Galina, Vera, and Andrei—and did all the housework to save her husband's time for creative work in science.

Wise men say that behind every great man is a great woman. The life of Leonid Maksimovich Brekhovskikh and his wife Lidiya Andreevna confirms the veracity of this statement.