Viktor Ilgisonis
Doctor of Physics and Mathematics
Professor,
research Institute of Physics and Technology
Moving forward.
1981
Graduated with honors from the Moscow Institute of Physics and Technology, specialty - “Experimental Nuclear Physics”, qualification - “engineer-physicist”.
1981 - 1984
Post-graduate student of I. V. Kurchatov Institute of Atomic Energy.
1984 - 2017
Worked his way up from Junior researcher to Director of the National Research Center “Kurchatov Institute”.
1987
Candidate thesis on “Stability of plasmas in closed magnetic traps with localized MHD stabilizer” was defended.
1996
Internship at the Institute for Plasma Physics of The Foundation for Fundamental Research on Matter (FOM), Nieuwegein, the Netherlands.
1997
Internship at The Courant Institute of Mathematical Sciences, CIMS, New York, USA.
1999 - 2001
Lectured at the Department of Mathematics of the Faculty of Physics at Lomonosov Moscow State University.
2004
Doctoral thesis on “Magnetohydrodynamic models of plasma: Lagrangian properties and the problem of stability” was defended. Academic degree - Doctor of Physics and Mathematics was awarded.
2007 - present
Head of the Department, Director of the Research Institute of Physics and Technology of RUDN University.
2002 - 2018
Associate professor, professor of Plasma Physics Department, Faculty of Experimental and Theoretical Physics, the National Research Nuclear University, Moscow Engineering Physics Institute (MEPhI).
2017 - present
Director for scientific and technical research and development of the State Atomic Energy Corporation “Rosatom”.
Teaching
Reads to RUDN University, Lomonosov Moscow State University, MEPhI students the following courses:
- Physics of nonlinear processes,
- Theoretical hydrodynamics,
- Equilibrium and stability of plasma.
The author of the following course-books and study guides:
- “The classical problem of the physics of hot plasmas”. V. I. Ilgisonis. / Study guide - M: Publishing house MEI, 2016, 326 p.|
The book deals with some of the key problems of physics of high-temperature plasma and magnetic fusion, which are considered to be classical and to which scientific thought returns from time to time due to the need to take into account new effects, expanding the scope of applicability, as well as due to progress in related scientific areas. Both well-known and original results obtained mostly in the works of the author are presented; some fairly universal mathematical methods and approaches are described, the productivity of which is demonstrated by relatively simple examples.
http://www.studentlibrary.ru/book/ISBN9785383009260.html - “Introduction to theoretical hydrodynamics”. V. I. Ilgisonis. / Study guide. M.: RUDN, 2010, 129 p.
The summary of the semester lecture course is given, which is designed for senior students who have attended University courses of Mathematical analysis, Partial differential equations, Theoretical mechanics and have an idea about the methods of vector analysis and calculus of variations. The course is focused not on the subsequent solution of applied problems of hydromechanics, but on teaching future theoretical physicists the necessary basics of field theory, beyond the traditional University courses of hydrodynamics and electromagnetism. The study guide is prepared at the Department of Experimental Physics of the Faculty of Physical, Mathematical and Natural Sciences.
http://www.studmedlib.ru/book/ISBN9785209035619.html
Science
- A new direction in the study of Magnetohydrodynamic generator (MHD) stability of liquid media, based on a systematic account of the variation procedure set invariant, not reducible to ordinary Casimir invariants was developed; new symmetries and conservation laws were found; for toroidal topology flows, a sufficient stability condition was obtained, the closest to the necessary one of all known today.
- An exhaustive set of invariants of linearized dynamics of an ideal liquid or plasma in a magnetic field was discovered.
- The paradox of the continuous transition from multi-liquid to single-liquid MHD models, the essence of which is in the spontaneous symmetry breaking during such a transition, was solved.
- A new type of MHD instability characteristic of long magnetic systems was discovered and investigated, and a method for its suppression was proposed.
- A formalism of three-dimensional description of the drift dynamics of magnetized plasma was proposed and developed, taking into account the effects of the finite Larmor radius of ions; a new physically correct scheme of breaking the chain of moment equations was developed.
- A new magnetic flux-rotational instability was discovered, the threshold of which in the dipole field characteristic of astrophysical objects is an order of magnitude lower than the threshold of the magneto-rotational instability.
- The theory of low-frequency ideal MHD modes in axisymmetric toroidal systems with toroidal and poloidal plasma flows, describing the coupling of Alfven and slow (sound) modes that determine the continuous spectrum of the rotating plasma was constructed; unstable modes for plasma with supersonic poloidal rotation were found and conditions for their stabilization due to the effect of engagement with Alfven modes were found; the possibility of global modes was proved.
- The theory of gradient-drift instability in Hall-effect thrusters was constructed.
Scientific interests
- Magnetic retention of high temperature plasma;
- Magnetohydrodynamics;
- Stability theory;
- Kinetics of high temperature magnetized plasma;
- Nonlinear dynamics.
The stability of gradient-drift waves in a Hall-type plasma thruster is investigated within the framework of two-fluid ideal magnetohydrodynamics. The analysis is based on the dispersion relation, which includes the effects of equilibrium electron current, finite ion flow velocity, electron inertia, electron temperature, magnetic field and plasma density gradients, and also the Debye length effects. The features of unstable modes are calculated along the thruster channel. Three spatially separated areas of instability are revealed: (i) the near-anode region with long-wavelength azimuthal oscillations, (ii) the main part of the acceleration channel with short-wavelength axial modes destabilized by macroscopic ion flow, and (iii) the plume region characterized by short-wavelength oblique waves.
Capillary-porous electrodes for plasma MHD devices are considered. The electrodes can be continuously renewable and allow one to use a scheme of the inverted MHD generator (i.e., MHD accelerator) as a thruster for interorbital flights. Two types of plasma acceleration are considered: (i) Lorentz force acceleration with a primary current perpendicular to the acceleration direction (Faraday scheme) and (ii) acceleration based on the Hall effect. In the first case, the thruster has advantages only at thrust powers exceeding 1 MW, while in the second case, the thrust and specific impulse are comparable with those of the known analogs (or even surpass them) already at powers of 500–1000 kW. The operating conditions of capillary-porous electrodes are formulated.
The phenomenon of large-scale discharge oscillations in Morozov’s stationary plasma thruster (SPT) is physically interpreted by analyzing global modes of gradient drift instability. The problem is solved using an ideal two-fluid hydrodynamic plasma model that includes the effects of stationary electron flow, electron inertia, and spatial inhomogeneities of the magnetic field and plasma density along the accelerating channel. The frequencies and axial structure of unstable eigenmodesare calculated for typical parameters of the SPT-100 thruster. The obtained spectrum is characterized by a finite set of long-wavelength azimuthal modes in the lower hybrid frequency range, which are predominantly localized in the near-anode region of the thruster. It is shown that the eigenmodes can form wave packets the main characteristics of which in the linear stage of instability coincide with the parameters of the experimentally observed large-scale azimuthal spoke-like structures. The influence of the thruster geometry (the length and width of the accelerating channel) on the frequency characteristics of oscillations and formation of beatings is investigated.
The strategic line of development of a nuclear power system based on fission and fusion reactors which ensures electricity generation on a specified scale, solves the fuel problem for a long-term outlook, and secures the lowest risk of environmental contamination is presented. A contemporary view of prospects of developing the nuclear power industry on the basis of replacement of thermal reactors in the future by fast reactors, owing to a long duration of this process and the necessity of additional resources of natural uranium, forces us to consider the possibility of implementation of this strategy as unlikely. In addition, the fuel cycle of fast reactors requires the quick reprocessing of the highly active spent fuel, and because of this, the fuel cycle will have a high risk of a negative radioactive effect on the environment. The transition of the nuclear power industry to fast reactors will lead to a full change of the infrastructure related to reactor construction and operation. In the development of a nuclear power system with fusion and fission reactors, the demands for natural uranium will correspond to current estimates of economically effective stockpiles, the risk of radioactive contamination of the environment associated with the spent fuel reprocessing will be the lowest, and the contemporary infrastructure of the nuclear power industry will be maintained, i.e., the prevalence of generating capacities based on thermal neutron reactors. Thus, the integration of nuclear power production by fusion and fission reactions into a unified system creates a significant synergetic effect, in which the deficiencies of each technology are compensated by another technology of nuclear power production.
The detailed analysis of stability of azimuthal oscillations in partially magnetized plasmas with crossed electric and magnetic fields is presented. The instabilities are driven by the transverse electron current which, in general, is due to a combination of E×B and electron diamagnetic drifts. Marginal stability boundary is determined for a wide range of the equilibrium plasma parameters. It is shown that in some regimes near the instability threshold, only the low-frequency long-wavelength oscillations are unstable, while the short-wavelength high-frequency modes are stabilized by the finite Larmor radius effects. Without such stabilization, the high-frequency modes have much larger growth rates and dominate. A new regime of the instability driven exclusively by the magnetic field gradient is identified. Such instability takes place in the region of the weak electric field and for relatively large gradients of plasma density (ρs/ln>1, where ρs is the ion-sound Larmor radius and ln is the scale length of plasma density inhomogeneity).
The gradient-drift instabilities of partially magnetized plasmas in plasma devices with crossed electric and magnetic fields are investigated in the framework of the two-fluid model with finite electron temperature in an inhomogeneous magnetic field. The finite electron Larmor radius (FLR) effects are also included via the gyroviscosity tensor taking into account the magnetic field gradient. This model correctly describes the electron dynamics for k┴ρe>1 in the sense of Padé approximants (here, k┴ and ρe are the wavenumber perpendicular to the magnetic field and the electron Larmor radius, respectively). The local dispersion relation for electrostatic plasma perturbations with the frequency in the range between the ion and electron cyclotron frequencies and propagating strictly perpendicular to the magnetic field is derived. The dispersion relation includes the effects of the equilibrium E×B electron current, finite ion velocity, electron inertia, electron FLR, magnetic field gradients, and Debye length effects. The necessary and sufficient condition of stability is derived, and the stability boundary is found. It is shown that, in general, the electron inertia and FLR effects stabilize the short-wavelength perturbations. In some cases, such effects completely suppress the high-frequency short-wavelength modes so that only the long-wavelength low-frequency (with respect to the lower-hybrid frequency) modes remain unstable.
It is shown that the surface with a constant mean curvature encloses the extremal volume among all toroidal surfaces of given area. The exact solution for the corresponding variational problem is derived, and its parametric analysis is performed in the limits of high and small mean curvatures. An absence of smooth torus with constant mean curvature is proved, and the extremal surface is demonstrated to have at least one edge located on the outer side of the torus.
Experiments with relativistic plasmas obtained and confined in a magnetic mirror under gyromagnetic autoresonance and their computer simulations are described. Plasma bunches with relativistic electrons are generated. The averaged energy of the electrons in the bunch is about few hundreds keV depending on the parameters of seed plasma, microwave electric field strength, and the rate of the pulse magnetic field increase. Varying the values of these parameters, it is possible to control the bunches.
The influence of the shape of the plasma cross section on the continuous spectrum of geodesic acoustic modes (GAMs) in a tokamak is analyzed in the framework of the MHD model. An expression for the frequency of a local GAM for a model noncircular cross section plasma equilibrium is derived. Amendments to the oscillation frequency due to the plasma elongation and triangularity and finite tokamak aspect ratio are calculated. It is shown that the main factor affecting the GAM spectrum is the plasma elongation, resulting in a significant decrease in the mode frequency.
Hall plasmas with magnetized electrons and unmagnetized ions exhibit a wide range of small scale fluctuations in the lower-hybrid frequency range as well as low-frequency large scale modes. Modulational instability of lower-hybrid frequency modes is investigated in this work for typical conditions in Hall plasma devices such as magnetrons and Hall thrusters. In these conditions, the dispersion of the waves in the lower-hybrid frequency range propagating perpendicular to the external magnetic field is due to the gradients of the magnetic field and the plasma density. It is shown that such lower-hybrid modes are unstable with respect to the secondary instability of the large-scale quasimode perturbations. It is suggested that the large scale slow coherent modes observed in a number of Hall plasma devices may be explained as a result of such secondary instabilities.
A set of reduced linear equations for the description of low-frequency perturbations in toroidally rotating plasma in axisymmetric tokamak is derived in the framework of ideal magnetohydrodynamics. The model suitable for the study of global geodesic acoustic modes (GGAMs) is designed. An example of the use of the developed model for derivation of the integral conditions for GGAM existence and of the corresponding dispersion relation is presented.
Ion sound instabilities driven by the ion flow in a system of a finite length are considered by analytical and numerical methods. The ion sound waves are modified by the presence of stationary ion flow resulting in negative and positive energy modes. The instability develops due to coupling of negative and positive energy modes mediated by reflections from the boundary. It is shown that the wave dispersion due to deviation from quasineutrality is crucial for the stability. In finite length system, the dispersion is characterized by the length of the system measured in units of the Debye length. The instability is studied analytically and the results are compared with direct, initial value numerical simulations.
The analytical solution for global geodesic acoustic modes (GGAMs) in a tokamak with a positive magnetic shear profile and a monotonic temperature profile is found in the framework of magnetohydrodynamic theory. The axisymmetric eigenvalue problem for perturbed pressure and electrostatic potential is formulated as a recurrent set of equations for poloidal Fourier harmonics. The integral condition for the existence of GGAMs is obtained. It is shown that the traditional paradigm of having a off-axis maximum of the local geodesic acoustic frequency is not necessary for the existence of GGAMs; a representative example is designed.
Analytical solutions for global geodesic acoustic modes in the plasma of a tokamak with circular concentric magnetic surfaces are obtained. In the framework of ideal magnetohydrodynamics, an integral equation for eigenvalues (dispersion relation) taking into account toroidal coupling between electrostatic perturbations and electromagnetic perturbations with the poloidal mode number |m| = 2 is derived. In the absence of such coupling, the dispersion relation yields only the standard continuous spectrum. The existence of a global geodesic acoustic mode is analyzed for equilibria with both on-axis and off-axis maxima of the local geodesic acoustic frequency. The analytical results are compared with results of numerical calculations.