To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Results in some directions of the target technology for research on high energy density and laser fusion at the Russian Federal Nuclear Centre–All-Russia Research Institute of Experimental Physics for the last three years are presented. The results of development of optical and X-ray methods of characterization and manufacturing techniques of targets for studying the equation-of-state at high pressures and the condensed rare gas targets for the influence of pulse-repeated laser irradiation are given.
Review of some research into laser thermonuclear fusion
carried out in Russian Federal Nuclear Center (RFNC-VNIIEF)
within the last several years is presented. The review
begins with a brief survey into ICF development in RFNC-VNIIEF
starting from A.D. Sakharov and S.B. Kormer's pioneer
proposals of the 1960s. The review concludes with the exposition
of historical background of the 10 TW ISKRA-4 and 100 TW
ISKRA-5 laser facilities creation and with the prospects
of the 300 kJ ISKRA-6 (λ= 0.35 μm) laser
development. The results of survey carried out at the ISKRA-5
facility are presented in the review. The high degree of symmetry
(nonuniformity < 3%) of irradiation of a DT-shell by the X-ray
emission made it possible to successfully conduct experiments
with the asymmetrical shells. The asymmetry was effected through
the asymmetrical Mg layers deposition on a spherically uniform
glass shell surface. The asymmetry impact on neutron yield and
the moment of neutron generation was investigated. The line
X-ray emission characteristics of the H-like and He-like
Ar, Fe, and Al ions were studied in another set of experiments.
Ar was doped into DT-gas, while Fe and Al were deposited
on the CH spherical hohlraums' inner surface. Development
of the Cherenkov radiation generator in which the electron
motion is actuated by the faster-than-light X-ray pulse
motion on the surface of a plane sample, being under voltage,
is reported. And in fine a brief description of experiments
carried out at the ISKRA-4 facility under the program of
turbulent mixing in plane multi layer targets is presented.
This paper is devoted to the investigation of powerful
laser pulse interaction with regularly and statistically
volume-structured media with near critical average density
and properties of laser-produced plasma of such a media.
The results of the latest experiments on laser pulse interaction
with plane foam targets performed on Nd-laser facilities
“ABC” in the ENEA-EURATOM Association (Frascati,
Italy) and “MISHEN” in the Troitsk Institute
of Innovation Thermonuclear Investigations (TRINITI, Troitsk
Russia), and J-laser “ISKRA-4” in the Russian
Federal Nuclear Center, All-Russian Scientific Research
Institute of Experimental Physics (RFNC-VNIIEF, Sarov,
Russia) are presented and analyzed. High efficiency of
the internal volume absorption of laser radiation in the
foams of supercritical density was observed, and the dynamics
of absorbing region formation and velocity of energy transfer
process versus the parameters of porous matter
are found. Some inertial confinement fusion (ICF) applications
based on nonequilibrium properties of laser-produced plasma
of a foam and regularly structured media such as the powerful
neutron source with yield of 109–1011
DT-neutrons per 1 J of laser energy, laser-produced X-ray
generation in high temperature supercritical plasma, and
the compact ICF target absorbers providing effective smoothing
and ablation are proposed.
The investigations of the influence of various
types of wavefront distortions, varying in time, on the
intensity distribution on the surface of a target are carried
out. It is shown that distortions of a wavefront, equivalent
to transverse displacement in time of a beam in far field
at an angle of approximately 10 diffraction angles, results
in practically full smoothing of a specl-structure of intensity
distribution. Creation of phase distortions of a beam assigned
as running in a cross section wave with an amplitude of
more than 3 radian and with a spatial size exceeding 20–30
times the size of the kinoform phase plate element, permits
us to reduce the depth of modulation in distribution of
intensity in far field also. The capability of application
is considered as a smoothing device of the dynamic plasma
layer, based on the volume-structured medium. The model
of energy transport process in such media is developed.
Matching of calculation and experimental results is conducted.
Results of turbulent mixing research of thin Al
and Au layers under laser acceleration of the three-laser
targets Si/Al/Au are presented. Analyses of experimental
data under the program SND-TUR, where the Nikiforov model
is used for turbulent mixing description, testify to the
essential impact of hot spots on the examined processes
in distribution of laser radiation intensity on the surface
of the target. Experimental setup on the laser beams'
smoothing by the “foam” coated on the target,
has been considered. The results of the first experiments
Two shells with the diameter of 0.8–0.9 mm
and a wall thickness of ≅1 μm were produced at
the Lebedev Physics Institute for the experiments conducted
at the ISKRA-5 facility. The results of two experiments
with the aforementioned shells conducted at the ISKRA-5
facility with the use of an indirect-drive set up. In one
of the experiments, the diameter of the golden hohlraum
was D = 2 mm while in the other it was D =
4 mm. In these experiments it was observed to be ≅4
times the difference of the average laser intensity on the
hohlraum surface. The results of computational analysis of the
experiments are also presented here.
Since 1973, research into the problem of laser
thermonuclear fusion has been carried out at VNIIEF. For
this purpose, laser iodine facilities ISKRA-4 and ISKRA-5
with the peak radiation power up to 100 TW have been created.
In the present work, the main stages of these facilities
creation, approaches to the selection of the pumping sources,
working media, optical scheme, radiation focusing system,
the system of the pumping sources energy feed, laser radiation,
and plasma parameters diagnostics methods are shown. There
are also presented types of the targets, filled with DT-gas,
in which the high temperature plasma is formed and its
parameters are studied. Data on values of neutron yield,
of X rays in wide energy range, degree of implosion, and
data on mix of heavy and light layers of matter are presented
The interaction of a plasma produced by irradiation of perforated foils with laser pulses was studied. The laser beam of the first harmonics of the iodine laser (λ = 1.315 μm) system PERUN was focused by anf/2 optics (f = 20 cm) on a hole in the foil target of high-Z material. The laser energy and the temporal shape of the pulses were monitored both before and behind the hole. Foils of two different materials (Pb, Cu) were used, and a series of hole diameters 2rH ranging from 100 μm to 500 μm were tested. The diameter of the laser focal spot 2r0 was about 150 μm. For hole diameters smaller than 300 μm, a shortening of the laser pulse was observed, demonstrating the effect of plasma shutter. The pulse shortening, which depends on the hole diameter, corresponds to the reduction in the pulse energy passing through the hole. An analysis of the experimental data is based on hydrodynamic computations, and the physics of the process is illustrated by a simple analytical model.
Email your librarian or administrator to recommend adding this to your organisation's collection.