Nikolay Fyodorovich Kovalev (born 27 February 1943) is a physicist, Doctor of Physical and Mathematical Sciences, and head of the Laboratory of High-Power Pulsed Microwave Sources at the Institute of Applied Physics of the Russian Academy of Sciences, laureate of the USSR State Prize [1][2]. He was among those whose pivotal contribution led, in 1972, to the creation of the first coherent electromagnetic radiation generator driven by a high-current electron accelerator — the relativistic backward-wave oscillator [3].
From Polytech to High-Current Electronics
He graduated from the Gorky Polytechnic Institute in 1966 and joined the Radiophysical Research Institute (NIRFI); from 1977 onward he worked at the Institute of Applied Physics of the Academy of Sciences as head of a laboratory [2].
He defended his Candidate's dissertation in 1983 and his Doctoral dissertation in 1992, both in the field of relativistic microwave electronics [2]. He has published more than 130 scientific articles and papers on gigawatt microwave electronics, strongly magnetized relativistic electron beams, and electrodynamics [2].
High-power electronics based on relativistic electron beams began in the 1970s, following the emergence of high-current charged-particle accelerators in the USSR and abroad [3].
| Year | Milestone |
|---|---|
| 1966 | graduated from the Gorky Polytechnic Institute |
| 1966–1977 | Scientific Research Radiophysical Institute |
| 1972 | participated in the creation of the first relativistic backward-wave oscillator |
| from 1977 | Institute of Applied Physics, head of laboratory |
| 1983 | Candidate of Physical and Mathematical Sciences |
| 1992 | Doctor of Physical and Mathematical Sciences |
The 1972 Backward-Wave Oscillator
The first coherent electromagnetic radiation generator driven by a high-current electron accelerator — the relativistic backward-wave oscillator — was created in a joint experiment by the Radiophysical Institute and the Physical Institute of the Academy of Sciences in 1972, at the initiative of Gaponov-Grekhov Andrey Viktorovich and Mikhail Rabinovich [3].
The generator was realized through the pivotal contributions of Kovalev, M. D. Rayzer, M. I. Petelin, A. V. Smorgonsky, and L. E. Tsopp; in terms of peak pulse power it surpassed all previous microwave radiation sources by several orders of magnitude [3].
Later, at the Institute of Applied Physics, relativistic versions of other microwave generators and amplifiers were proposed and demonstrated experimentally — the traveling-wave tube, the orotron, the magnetron, and the gyrotron; these efforts involved Kovalev together with M. I. Petelin, V. L. Bratman, N. S. Ginzburg, E. B. Abubakirov, and G. G. Denisov [3].
The Laboratory
According to the Institute of Applied Physics 2015 annual report, Kovalev led the research topic "Investigation and Development of Gigawatt Backward-Wave Oscillators and Their Output Coupling Systems" — work of the Laboratory of High-Power Pulsed Microwave Sources carried out jointly with the engineering design sector [1].
Experiments conducted that year demonstrated that a backward-wave oscillator with longitudinal slots allows the pulse duration of generation to be increased by more than threefold and the build-up time of generation to be reduced to two or three nanoseconds in the three-centimeter band; the result was obtained jointly with the Institute of Electrophysics of the Ural Branch of the Academy of Sciences [1].
His second research topic was "Thin-Walled Electron Beams for Relativistic Backward-Wave Oscillators with Short Transient Times": properties of beams produced from explosive-emission edge cathodes, explanation of azimuthal magnetic field smoothing, and splitting of electron jets in multi-jet beams [1].
Such generators are no mere laboratory curiosity: in collaboration with a British company, a nanosecond gigawatt radar called NAGIRA — based on a high-current electron accelerator and a relativistic backward-wave oscillator — was developed and is capable of detecting small moving targets against a background of strong ground clutter [3].
Teaching and Reviews
Kovalev is among the institute's staff who also teach at Nizhny Novgorod universities — at the radiophysics faculty and at Vysshaya Shkola of General and Applied Physics at Lobachevsky University [1].
In 2016, together with M. I. Fuks and E. Schamiloglu, he published the review article "Stages in the Development of Relativistic Magnetrons" in the journal Izvestiya Vuzov. Applied Nonlinear Dynamics — fourteen pages on the history of devices in which electrons move in crossed fields [4].
The High-Frequency Relativistic Electronics Department of the Institute of Applied Physics currently comprises laboratories of high-power microwave systems for accelerator applications, short-wavelength microwave generators, and spatially extended generators and amplifiers [5].
The laboratory he heads operates at the institute on Ulyanova Street, 46 [3].
Sources
- ipfran.ru — IAP RAS — 2015 Annual Report: Laboratory of High-Power Pulsed Microwave Sources, head N. F. Kovalev (archive)
- andjournal.sgu.ru — Izvestiya Vuzov. Applied Nonlinear Dynamics (archive)
- ipfran.ru — IAP RAS — Research Directions: Relativistic Microwave Electronics
- andjournal.sgu.ru — Izvestiya Vuzov. Applied Nonlinear Dynamics — Fuks M. I., Schamiloglu E., Kovalev N. F. Stages in the Development of Relativistic Magnetrons, 2016, vol. 24, iss. 6, p. 39 (archive)
- ipfran.ru — IAP RAS — Institute Structure: Department of High-Frequency Relativistic Electronics and its laboratories