Elaboration of the concept of a fusion reactor based on toroidal magnetic traps of a "stellarator" type.
Equilibrium, stability and confinement of a high-temperature plasma in stellarators/torsatrons.
HF heating of plasma and current drive in toroidal magnetic systems.
Diagnostics of high-temperature plasma.
Development of high-power quasistationary plasma accelerators and their application.
Plasma technologies.
Basic results of recent years
STELLARATORS
Methods of optimizing magnetic
field configurations in stellarators are developed in order to
improve equilibrium and stability of plasma and to reduce
neoclassical losses. The concept of power-free magnetic systems
for stellarators of a "torsatron" type is developed.
On the basis of this concept a
torsatron with a divertor "Uragan-3" ("3M")
is constructed. Methods of stellarator magnetic coil alignment
and magnetic surface mapping are proposed and used for optimizing
the "Uragan-3M" magnetic configuration. A method of
magnetic island suppression in torsatrons is offered. The
influence of the helical harmonic spectrum on collisionless
plasma transport is investigated. The researchers have developed
and used the concept of creation and heating of currentless
plasma with absorption of RF power in the ion cyclotron/Alfen
frequency range. Helical frame antennas with a protective
titanium nitride coating, capable to deliver RF power up to 1 MW
to a plasma, are devised. Plasma creation and the particle
density build-up is a consequence of RF power absorption by
electrons as different-type plasma waves are sequentially
excited. Confinement of currentless plasma, created at RF power
absorption, is investigated. For 0.2 MW RF power absorption, the
quasistationary currentless plasma is obtained with ion
temperature up to 1.1 keV and energy content close to
equilibrium-limited one. Under such limiting regimes relaxation
fluctuations of parameters are found, interpreted as a
consequence of high-beta plasma instability predicted by theory.
It is established that the electron heat conductivity is close to
neoclassical in the plasma center and is abnormally high at the
plasma periphery. Particle diffusion in the confinement region,
in the ergodic magnetic layer and divertor flows is investigated.
It is shown that in a greater part of a plasma column the
particle diffusion is close to neoclassical. Plasma shielding
efficiency in the ergodic magnetic layer in relation to light and
heavy impurities is investigated.
Studies by theory are made of
the confining properties of a torsatron magnetic configuration.
This configuration with a small helix angle and additional
longitudinal field is realized in "Uragan-2M" machine.
It is shown that the minimization of the magnetic-field helical
inhomogeneity in the torsatron ensures an essential reduction of
neoclassical transport coefficients in comparison with other
stellarator installations.
TORSATRON "URAGAN-2M"
The experimental research of
magnetic field configurations in the torsatron
"Uragan-2M" has confirmed the results of numerical
calculations. The RF method devised for plasma creation and
heating, is based on the excitation of slow and fast waves in the
plasma in the ion cyclotron frequency range by the use of
antennas with developed radiating surface. The RF complex for
"Uragan-2M", including a generator and antennas, is
created to deliver RF power up to 5 MW to the plasma.
The IPP scientists pioneered the
idea of effective RF heating of plasma in tokamaks at frequencies
close to the ion cyclotron resonance using a small addition of
resonant ions. Theory and methods are developed for high-powered
RF plasma heating and current drive in large tokamaks on
frequencies close to the ion cyclotron resonance. Complexes for
RF plasma heating in the tokamak T-10 (RSC Kurchatov Institute,
Moscow) and torsatron TJ-IU (CIEMAT, Madrid) are created.
QUASISTATIONARY PLASMA ACCELERATORS
The concept of devising
high-power quasistationary plasma accelerators (QSPA) for fusion
and technological applications is developed together with RSC
Kurchatov Institute, Moscow. A few models of QSPA are constructed
and investigated.
THE PLASMA ACCELERATOR QSPA X-50
The QSPA X-50 experiments
confirm the basic idea of the concept, i.e., a quasistationary
mode of acceleration with ion current transport in the principal
channel of the two-step accelerator is realized. It is shown that
QSPA generates high-power plasma flows with the energy density
sufficient to stimulate the conditions on in-chamber elements of
a tokamak - reactor at disruption instability. Experiments are
made to study the interaction of high-power plasma flows on the
surface; positive effect of surface screening with a dense plasma
cushion resulting from the action of the plasma flow front is
found.
DIAGNOSTICS OF PLASMA
A number of new approaches in
diagnostics of the fusion reactor - tokamak plasma are developed,
including the dual-polarization microwave reflectometry and
magnetic diagnostics as tools of restoring current and plasma
density profiles.