Zbigniew Peradzyński – the Winner of the Polish Mathematical Society’s Prize

Zbigniew Peradzyński (dla przyjaciół po prostu Zbyszek) jest laureatem nagrody głównej im. Hugona Steinhausa w dziedzinie matematyki stosowanej. Z werdyktu jury dowiadujemy sie, ze nagroda została przyznana za całokształt działalnosci, miedzy innymi za teoretyczne badania silników jonowych i badania w zakresie teorii nadciekłego helu.

Professor Zbigniew Peradzyński (for friends simply Zbyszek) is a recipient of the Steinhaus Prize in the field of Applied Mathematics, in year 2011. According to the jury's verdict, the prize has been awarded for Zbyszek's overall scientific activity, in particular for his contribution to the theoretical research of ion thrusters and his work on the superfluid helium theory. The verdict is based on papers, which are enumerated in the references.  Zbyszek first showed his interest in space journeys in high school when he established with his schoolmate a rocket club. The club was located in the basement of the community center. Despite a few minor explosions and incidental fires, young astronauts managed to survive, return to the Earth and win the first prize in the state competition for young researchers (their theoretical papers were found especially interesting). It is worth mentioning that the name of Zbyszek's schoolmate was Zbyszek Kłos who now is a professor and who for many years has been a director of the Space Research Center.  I associate ion engines mainly with science fiction books, where ion thrusters were long ago applied for spacecrafts propulsion.  In real life, however, although it seems that Americans were pioneers in the construction of this kind of engines, the Russians first used them. These engines were applied to stabilize Soviet satellites in 1970s. The Americans had meanwhile very efficient chemical correction boosters. Ion engines, especially those based on the Hall effect are rather used for long-distance missions such as Deep Space1, Hayabusa, and Dawn. They are handy when very small levels of thrust are needed but at the same time a long and flawless functioning is required. Ion engines can be much more effective than classical ones. Zbigniew Peredzyński, together with a few other accomplices from Poland and one French graduate student, participated as a Polish coordinator in a French research program devoted to plasma engines based on the Hall effect. The Polish team was regarded, also from the financial perspective as a part of the French GDR 2759 CNRS/CNES/SNECMA/Universités (i.e. Groupement de Recherches 2759 "Propulsion spatiale à Plasma"), which was formed by eight French laboratories.  Polish contribution consisted mainly of creating a mathematical model based on the hydrodynamic equations and describing the behavior of three-component, two-temperature plasma in a thruster. In subsequent stages, the properties of the hydrodynamic model were investigated. This included writing  codes for numerical solvers, making calculations, and comparing them with  features resulting from experiments. Other teams took care of experimental research or dealt with the development of kinetic and hybrid models. The hydrodynamic model proved to be very useful for constructors due to its simplicity, clarity, and because it facilitated physical interpretations of results as well as it guaranteed fast computations. This model predicted the majority of observed phenomena such as instability and plasma flow oscillations. For instance, persistently appearing low frequency oscillations of the discharge current have the same character as periodic solutions in biological predator-prey systems. Here, electrons created in the ionization process play the role of predators, while neutral atoms are the prey. A French engine manufacture company SNECMA deeply appreciated Polish research results and it consequently decided to offer a financial support for two further PhD dissertations in Poland.