  Samuil Kaplan (1921-1978) was a productive and famous astrophysicist. He was
affiliated with a number of scientific centers in different cities of former
Soviet Union. The earliest 13 years of his career, namely in the 1948-1961
years, he worked in Lviv University in Ukraine (then it was called the
Ukrainian Soviet Socialist Republic). In the present paper, the Lviv period of
his life and scientific activity is described on the basis of archival
materials and his published studies. Kaplan arrived in Lviv in June 1948, at
the same month when he obtained the degree of Candidate of science. He was a
head of the astrophysics sector at the Astronomical Observatory of the
University, was a professor of department for theoretical physics as well as
the founder and head of a station for optical observations of artificial
satellites of Earth. He was active in the organization of the astronomical
observational site outside of the city. During the years in Lviv, Kaplan wrote
more than 80 articles and 3 monographs in 9 areas. The focus of his interests
at that time was on stability of circular orbits in the Schwarzschild field, on
white dwarf theory, on space gas dynamics, and cosmic plasma physics, and
turbulence, on acceleration of cosmic rays, on physics of interstellar medium,
on physics and evolution of stars, on cosmology and gravitation, and on optical
observations of Earth artificial satellites. Some of his results are
fundamental for development of theory in these fields as well as of
observational techniques. The complete bibliography of his works published
during the Lviv period is presented. Respective scientific achievements of
Samuil Kaplan are reviewed in the light of the current state of research in
these areas.
