Sergei Ivanovich Anisimov

Sergei Ivanovich Anisimov, an outstanding theoretical physicist, died of natural causes on 15 October 2019. His name is closely linked to physical hydrodynamics, physics of high energy density, and plasma physics. We will miss his scientific leadership and anticipate his contributions to be a source of inspiration for new generations of researchers.

Anisimov had a remarkable research career. He was born in Leningrad (USSR) on 11 December 1934. He graduated in 1958 from the Leningrad Polytechnic Institute (St. Petersburg Technical University, Russia). He received his PhD in 1961 at the Institute of Physics (Academy of Sciences, Belarus) and his doctor of sciences degree in 1970 at the Institute of Physical Problems (Academy of Sciences, USSR). He started his research career in Leningrad in 1958 at the Ioffe Institute for Physics and Technology (Academy of Sciences, USSR), and continued 1959–65 in Minsk in Belarus at the Institute of Physics. In 1965 he was invited to be the head of the department of physical hydrodynamics and plasmas at the newly organized Institute of Theoretical Physics (Academy of Sciences, USSR)—now the famous Landau Institute for Theoretical Physics. After that his scientific activity was closely linked with that institute (1965–2019). He was also professor and the director of the Laboratory of Nonlinear Optics at the Moscow Institute for Physics and Technology (1967–94), and he served from 1988–94 as head of theory department at the Joint Institute of High Temperatures (Academy of Sciences, USSR). In 1987 Anisimov was elected to the Academy of Sciences of the USSR. He published over 250 papers on plasma physics, laser fusion, light–matter interaction, physics of high energy density, and condensed matter.

A prominent work of Anisimov is the theory of interaction of ultrashort laser pulses with matter, which anticipated the femtosecond laser technology (Nobel Prize in Physics 2018 to Donna Strickland and Gerard Mourou). His two-temperature model, which brought him world recognition, became an essential part of the physics of light–matter interaction and femtosecond lasers.

Anisimov made a number of fundamental contributions to inertial confinement fusion and to kinetics and hydrodynamics of thermonuclear combustion of microtargets. He identified criteria for ignition, discovered the phenomenon of repeated target collapse, and established optimal concentrations for thermonuclear fuel components. He also made pioneering contributions to large-scale numerical simulations, including the very first simulations of Langmuir wave collapse, which is the key mechanism for generation of high-energy electrons in thermonuclear targets, as well as the first particle-in-cell numerical simulations with collisions, and molecular dynamics simulations of complex processes in shock compressed matter at extreme conditions. His scientific achievements in the field of plasma physics were recognized with the Alexander von Humboldt Prize (1992) and the Landau–Spitzer Prize (2012) of the American Physical Society.

Equally important among Anisimov’s contributions are theories of the polymer ablation and the multiquantum photoelectric effect in metals under intense laser radiation. These results, including the photophysical, photochemical, and thermal ablation mechanisms, explained a broad set of experiments. He developed the theory for optical breakdown of dielectrics, provided the understanding of physics of nonsteady processes at high energy densities, and developed original results in laser-induced evaporation. For his contributions to the physics of interaction of ultrashort laser pulses with condensed matter, he was awarded the Stoletov Prize (2011) in Physical Sciences by the Russian Academy of Sciences.

Anisimov was actively involved in the Vega program—a prominent project in the Soviet space program studying Venus, Halley’s Comet, and outer space. For his remarkable work within the program on design and development for space probes of cosmic dust, he was awarded the USSR State Prize in Science and Technology (1986).

Anisimov was an active member of executive committees of international physics unions, scientific councils, and editorial boards. For his fruitful scientific activities, he was awarded the Order of the Badge of Honor and medals of the USSR and the Russian Federation. Anisimov’s work had a remarkable impact on the international research community, including his collaborations with leading research centers in Europe, Japan, and the US, and his involvement in the Turbulent Mixing and Beyond program.

Anisimov was a successful research adviser and mentor. His scientific school includes over 30 PhDs and 7 doctors of sciences and retains leadership in the fields of physical hydrodynamics and high energy density physics. He motivated his junior colleagues to work on challenging and fundamental problems, and he endorsed the development of group theory of fluid instabilities and mixing, molecular dynamics simulations of complex high- rate processes involving phase transitions, and the theory of interface dynamics.

Sergei Ivanovich Anisimov was a man of broad education, sophisticated culture, and deep science. He will be missed by his many friends and colleagues all over the world.