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1.
Sergey Yu. Gus’kov 《Journal of Russian Laser Research》2010,31(6):574-588
We review the results of experimental and theoretical studies of the properties of a nonequilibrium plasma produced from volume-structured
media, containing micro- and nano-size internal elements, under laser-pulse irradiation. We consider two types of materials,
i.e., regularly and stochastically structured materials. The first type is either a set of flat layers or cylindrical and
spherical shells of micrometer thickness, and the second type is either foams of light elements or light foams containing
clusters of heavy elements with dimensions in the range of 10–100 nm. We study the properties of high-temperature laser-produced
plasmas of such materials and applications directed to developing the design of inertial confinement fusion (ICF) targets
and creating powerful sources of thermonuclear neutron and soft X-ray emission initiated by the laser pulse. The foam materials
can be used as absorbers capable of providing homogeneity of laser-energy absorption by the target. A neutron yield up to
1014−1015 DT neutrons per shot can be achieved by heating regularly structured materials using a laser pulse in the regime of the
consequent thermal explosions of solid elements containing isotopes of hydrogen. Laser-radiation conversion into soft X-ray
emission with the efficiency controlled in a wide range may be realized in laser-produced plasmas of porous media doped with
clusters of heavy elements. In particular, such a material can be used as an absorber–converter of laser radiation in inertial
confinement fusion targets. Under direct irradiation of an ICF target by a laser pulse, such a converter can provide transformation
of 20–30% of the absorbed laser energy into the energy of X-ray radiation transferred to thermonuclear capsules. 相似文献
2.
An equation describing evolution of a curved deflagration front of finite thickness is obtained for the case of an arbitrary
equation of state of the “fuel”, an arbitrary type of energy release and an arbitrary type of thermal conduction. The equation
is complemented by conservation laws for the mass flux and the momentum flux through the deflagration front of finite thickness.
As an illustration of the method, the growth rates and the cutoff wavelengths for the linear stage of the flame instability
are calculated for the case of a flame in an ideal gaseous fuel and for the case of a thermonuclear deflagration propagating
in a strongly degenerate matter of white dwarfs.
Zh. éksp. Teor. Fiz. 111, 514–527 (February 1997)
Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor. 相似文献
3.
A. A. Andreev S. Yu. Gus’kov D. V. Il’in A. A. Levkovskii V. B. Rozanov V. E. Sherman 《Journal of Experimental and Theoretical Physics》2001,92(1):69-77
The thermonuclear gain G for bulk and spark ignitions are calculated using a mathematical simulation of thermonuclear combustion in a DT plasma of laser targets for various parameters of the target plasma and (isobaric and isochoric) ignitors. The critical parameters of ignitors at which an effective nuclear burst occurs with G ~ 100 are calculated. It is shown that a further increase in the temperature and size of the ignitors virtually does not affect the efficiency of DT fuel burnup. Irrespective of the ignition technique, the value of G can be estimated with the help of a simple asymptotic formula. At the same time, the critical parameters of ignitors are determined to a considerable extent by the mode of ignition and by the target parameters. Spark ignition with an isochoric ignitor corresponding to the fast ignition mode is considered in detail. It is shown that the main critical parameter for optimal isochoric ignitors is their thermal energy liberated upon absorption of an auxiliary ultrashort laser pulse. The critical values of this energy are calculated. 相似文献
4.
In depth fusion flame spreading with a deuterium-tritium plane fuel density profile for plasma block ignition 下载免费PDF全文
B. Malekynia S. S. Razavipour 《中国物理 B》2012,(12):317-321
<正>Solid-state fuel ignition was given by Chu and Bobin according to the hydrodynamic theory at x = 0 qualitatively. A high threshold energy flux density,i.e.,E* = 4.3×1012 J/m2,has been reached.Recently,fast ignition by employing clean petawatt-picosecond laser pulses was performed.The anomalous phenomena were observed to be based on suppression of prepulses.The accelerated plasma block was used to ignite deuterium-tritium fuel at solid-state density. The detailed analysis of the thermonuclear wave propagation was investigated.Also the fusion conditions at x≠0 layers were clarified by exactly solving hydrodynamic equations for plasma block ignition.In this paper,the applied physical mechanisms are determined for nonlinear force laser driven plasma blocks,thermonuclear reaction,heat transfer, electron-ion equilibration,stopping power of alpha particles,bremsstrahlung,expansion,density dependence,and fluid dynamics.New ignition conditions may be obtained by using temperature equations,including the density profile that is obtained by the continuity equation and expansion velocity.The density is only a function of x and independent of time.The ignition energy flux density,Et*,for the x≠0 layers is 1.95×1012 J/m2.Thus threshold ignition energy in comparison with that at x = 0 layers would be reduced to less than 50 percent. 相似文献
5.
A new method of cylindrical cumulation of fast ions undergoing ponderomotive acceleration at the focus of a high-power subpicosecond
laser is proposed. When a laser beam is focused in a preionized gas at a ring focus, radial acceleration of ions by the ponderomotive
force occurs. The ions accelerated from the inner side of the ring form a cylindrical shock wave converging toward the axis.
As the shock wave cumulates, the ion density increases rapidly and the ion-ion collision probability increases along with
it. A numerical simulation for a ~100 TW subpicosecond laser pulse predicts the generation of up to 200 keV ions and up to
100-fold volume compression of the plasma in a cylinder ~1 μm in diameter. The lifetime of the dense plasma filament over
the length of the laser caustic is several picoseconds. It is suggested that laser cumulation of ions be used for the production
of a bright and compact subpicosecond source of fast neutrons, media for x-and γ-ray lasers, and multiply-charged ions and for the initiation of nuclear reactions.
Pis’ma Zh. éksp. Teor. Fiz. 69, No. 1, 20–25 (10 January 1999) 相似文献
6.
T. Zh. Esirkepov Y. Sentoku K. Mima K. Nishihara F. Califano F. Pegoraro N. M. Naumova S. V. Bulanov Y. Ueshima T. V. Liseikina V. A. Vshivkov Y. Kato 《JETP Letters》1999,70(2):82-89
Ion acceleration by petawatt laser radiation in underdense and overdense plasmas is studied with 2D3V-PIC (Particle in Cell)
numerical simulations. These simulations show that the laser pulse drills a channel through the plasma slab, and electrons
and ions expand in vacuum. Fast electrons escape first from the electron-ion cloud. Later, ions gain a high energy on account
of the Coulomb explosion of the cloud and the inductive electric field which appears due to fast change of the magnetic field
generated by the laser pulse. Similarly, when a superintense laser pulse interacts with a thin slab of overdense plasma, its
ponderomotive pressure blows all the electrons away from a finite-diameter spot on the slab. Then, due to the Coulomb explosion,
ions gain an energy as high as 1 GeV.
Pis’ma Zh. éksp. Teor. Fiz. 70, No. 2, 80–86 (25 July 1999)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
7.
G. S. Sarkisov V. Yu. Bychenkov V. T. Tikhonchuk A. Maksimchuk S. Y. Chen R. Wagner G. Mourou D. Umstadter 《JETP Letters》1997,66(12):828-834
We report the first interferometric observations of the dynamics of electron-ion cavitation of relativistically self-focused
intense 4 TW, 400 fs laser pulse in a He gas jet. The electron density in a channel 1 mm long and 30 μm in diameter drops
by a factor of approximately 10 from the maximum value of ∼8×1019 cm−3. A high radial velocity of the plasma expansion, ∼3.8×108 cm/s, corresponding to an ion energy of about 300 keV, is observed. The total energy of fast ions is estimated to be 6% of
the laser pulse energy. The high-velocity radial plasma expulsion is explained by a charge separation due to the strong ponderomotive
force. This experiment demonstrates a new possibility for direct transmission of a significant portion of the energy of a
laser pulse to ions.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 12, 787–792 (25 December 1997)
Published in English in the original Russian journal. Edited by Steve Torstveit. 相似文献
8.
A. E. Bugrov S. Yu. Gus’kov V. B. Rozanov I. N. Burdonskii V. V. Gavrilov A. Yu. Gol’tsov E. V. Zhuzhukalo N. G. Koval’skii M. I. Pergament V. M. Petryakov 《Journal of Experimental and Theoretical Physics》1997,84(3):497-505
We have experimentally investigated the processes of laser light absorption and energy transfer in porous targets made of
“agar-agar” (C14H18O7) with an average density of 1–4 mg/cm3 illuminated by the focused beam of a neodymium laser with an intensity of 1014 W/cm2 within a pulse of duration 2.5 ns. Many important scientific and technical problems, e.g., inertial-confinement thermonuclear
fusion, the creation of lasers in the x-ray regime, and the modeling of astrophysical phenomena under laboratory conditions,
can be successfully addressed by using low-density porous media as components of such targets. In our experiments with porous
targets of variable density and thickness we used optical and x-ray diagnostic methods, which ensured that our measurements
were made with high temporal and spatial resolution. We show that a region forms within the porous target consisting of a
dense high-temperature plasma which effectively absorbs the laser radiation. Energy is transferred from the absorption region
to the surrounding layer of porous material at up to 2×107 cm/s. Experimental data are in good agreement with the predictions of our theoretical model, which takes into account the
specific features of absorption of laser radiation in a porous material and is based on representing the energy transfer within
the material as a hydrothermal wave.
Zh. éksp. Teor. Fiz. 111, 903–918 (March 1997) 相似文献
9.
A. M. Urnov J. Dubau A. Ya. Faenov T. A. Pikuz I. Yu. Skobelev J. Abdallah R. E. H. Clark J. Cohen R. P. Johnson G. A. Kyrala M. D. Wilke A. L. Osterheld 《JETP Letters》1998,67(7):489-494
A new type of quasicontinuous emission spectrum from a femtosecond laser plasma near the Lyα line of H-like ions is obtained and interpreted. It is shown that these spectra are emitted by multiply charged hollow ions,
which are present in the plasma on account of its ultrahigh density, which, in turn, is due to the use of high-contrast laser
pulses for producing the plasma. A new spectroscopic approach based on analysis of the composition of spectral complexes of
hollow ions is discussed.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 7, 467–472 (10 April 1998) 相似文献
10.
We present a study of the effect of laser pulse temporal profile on the energy /momentum acquired by the ions as a result of the ultraintense laser pulse focussed on a thin plasma layer in the radiation pressure-dominant (RPD) regime. In the RPD regime, the plasma foil is pushed by ultraintense laser pulse when the radiation cannot propagate through the foil, while the electron and ion layers move together. The nonlinear character of laser–matter interaction is exhibited in the relativistic frequency shift, and also change in the wave amplitude as the EM wave gets reflected by the relativistically moving thin dense plasma layer. Relativistic effects in a high-energy plasma provide matching conditions that make it possible to exchange very effectively ordered kinetic energy and momentum between the EM fields and the plasma. When matter moves at relativistic velocities, the efficiency of the energy transfer from the radiation to thin plasma foil is more than 30% and in ultrarelativistic case it approaches one. The momentum /energy transfer to the ions is found to depend on the temporal profile of the laser pulse. Our numerical results show that for the same laser and plasma parameters, a Lorentzian pulse can accelerate ions upto 0.2 GeV within 10 fs which is 1.5 times larger than that a Gaussian pulse can. 相似文献
11.
It is shown that precompression of matter ahead of the thermonuclear burn wave front can occur in the central volume of a
multilayer cylindrical system under conditions of radiative energy transfer outside the region of wave propagation. The degree
of compression is sufficient for the development of a self-maintained wave of fusion reactions.
Pis’ma Zh. éksp. Teor. Fiz. 66, No. 12, 783–786 (25 December 1997) 相似文献
12.
S. V. Latyshev 《Technical Physics》1997,42(7):828-831
The potential possibilities of a plasma heated by laser radiation as a negative-ion source are analyzed theoretically. It
is shown that the efficiency of negative-ion formation in a laser plasma in the heating phase reaches 1015−1016 ions/J when the parameters of the laser radiation are optimally adjusted.
Zh. Tekh. Fiz. 67, 117–120 (July 1997) 相似文献
13.
V. P. Krainov 《Physics of Atomic Nuclei》2014,77(8):1005-1018
Thermonuclear fusion induced by the irradiation of solid deuterated cluster targets and foils with fields of strong femtosecond and picosecond laser pulses is discussed. The thermonuclear-fusion process D(d, n)3He in a collision of two deuterons at an energy of 50 to 100 keV in a deuterium cluster target irradiated with a strong laser pulse is discussed. A theory of thermonuclear fusion proceeding upon the irradiation of clusters formed by deuterium iodide (DI) molecules with the field of a superintense femtosecond laser pulse is developed. This theory is based on an above-barrier process in which the sequential multiple inner ionization of atomic ions within a cluster is accompanied by field-induced outer ionization. The yield of neutrons from thermonuclear fusion in a deuteron-deuteron collision after the completion of a laser pulse is calculated. The yield of neutrons is determined for the thermonuclear-fusion reaction proceeding in the interaction of an intense picosecond laser pulse with thin TiD2 foils. A multiple ionization of titanium atoms at the front edge of the laser pulse is considered. The heating of free electron occurs in induced inverse bremsstrahlung in the process of electron scattering on multiply charged titanium ions. The yield of alpha particles in the thermonuclear-fusion reaction involving protons and 11B nuclei that is induced in microdrops by a strong laser field is determined. Experimental data on laser-induced thermonuclear fusion are discussed. 相似文献
14.
V. Ya. Aleshkin S. A. Akhlestina B. N. Zvonkov N. B. Zvonkov I. G. Malkina E. A. Uskova 《JETP Letters》1998,68(1):91-96
A new method of obtaining quantum-size GaAs1−x
Sbx (x⩽0.45) layers is proposed. The method consists in laser vaporization of solid metallic antimony near the substrate directly
in the reactor. The antimony concentration is set by the antimony sputtering time with the arsine flux shut off. The polarization
of the photoluminescence of the obtained layers indicates the formation of quantum wires. The heterostructures obtained are
used to fabricate laser diodes.
Pis’ma Zh. éksp. Teor. Fiz. 68, No. 1, 84–88 (10 July 1998) 相似文献
15.
V. Yu. Bychenkov V. T. Tikhonchuk S. V. Tolokonnikov 《Journal of Experimental and Theoretical Physics》1999,88(6):1137-1142
A technique is suggested for triggering nuclear reactions by accelerating ions with a powerful ultrashort laser pulse in a
plasma. The underlying idea of the suggested compact “reactor” is utilization of high-energy ions accelerated by the charge-separation
electrostatic field in the direction perpendicular to the laser beam axis in a gas-filled capillary. Accelerated ions with
energies of several MeV penetrating the target from the inside surface of a channel give rise to nuclear reactions which can
be used to create a compact source of fast neutrons and neutrons of intermediate energies for generating various (short-and
long-lived, light and heavy) isotopes, for generating gamma radiation over a broad energy range, for making sources of light
ion and induced radioactivity. The yield of the corresponding nuclear reactions as a function of the laser beam parameters
has been investigated. The suggested technique for triggering nuclear reactions provides a practical tool for studies of nuclear
transformation on the pico-and nanosecond scales, which cannot be achieved using other methods.
Zh. éksp. Teor. Fiz. 115, 2080–2090 (June 1999) 相似文献
16.
T. V. Panchenko 《Physics of the Solid State》1998,40(3):415-419
The temperature dependence of the impurity optical absorption of nominally pure Bi12SiO20 (BSO) crystals and BSO crystals doped with Ga, Cr, Mn, and Ag ions is investigated. A method is proposed for determining
the thermal activation energy, and certain properties of deep levels are found.
Fiz. Tverd. Tela (St. Petersburg) 40, 452–457 (March 1998) 相似文献
17.
A theory of thermonuclear fusion caused by the irradiation of deuterium-iodide clusters with the field of a superatomic femtosecond laser pulse is developed. It is based on considering the process in which the sequential above-barrier multiple internal ionization of atomic ions within a cluster is accompanied by external field ionization. The theory is illustrated by taking the example of a cluster that is formed by 106 molecules of deuterium iodide and which is irradiated with a laser pulse of duration 50 fs and intensity 2×1018 W/cm2 at the peak. This case is dominated by I26+ atomic ions. The yield of neutrons from thermonuclear fusion in a deuteron-deuteron collision upon the passage of a laser pulse is calculated. The result is 105 neutrons per laser pulse. The mean kinetic energy of deuterons is estimated at 50 keV. Owing to induced inverse bremsstrahlung in scattering on multiply charged atomic ions, the electron temperature increases up to 28 keV. The role of the Mie resonance in the heating of the electron component is discussed. 相似文献
18.
We investigate the efficiency of inertial fusion target compression, where at the initial time moment the thermonuclear fuel
is in a two-phase state and has the form of two adjacent layers — the external DT-liquid layer and the internal DT-ice layer.
We study this problem for the fast ignition targets, where the ultimate final density of the thermonuclear matter is of a
special importance. We take the simplest type of a fast ignition target, which corresponds to the technical justification
of the HiPER Project aimed at demonstrating fast ignition at the compressing laser pulse energy ~100 kJ. Such a target presents
a spherical DT-ice shell coated with a thin polymer film. We obtain the dependence of the final target density on the mass
fraction of the DT-matter liquid phase and formulate the requirements on the admissible concentration of liquid phase if the
decrease in the DT-fuel final density does not exceed 10%. We find the criterion for choosing the laser-pulse duration which
provides the minimum decrease in the final density of the target containing DT-matter in the initial two-phase state. 相似文献
19.
S. Yu. Gus'kov E. I. Levanov V. B. Rozanov N. G. Sirotenko P. P. Volosevich 《Journal of Russian Laser Research》1996,17(1):15-30
One-dimensional numerical calculations are used to explore the possibility of thermonuclear fuel “ignition” (achieving an energy gainG ~ 1) in two-cascade laser-fusion targets with a relatively small aspect ratio for the inner shell. It is demonstrated that the parameters of the laser-produced thermonuclear plasma for a laser pulse energy of 200 kJ, various wavelengths of the laser radiation, and a simple pulse shape closely correspond to the “ignition” state for a target with an inner shell having an aspect ratio of ~ 3–10. This is indicative of the high energy efficiency of two-cascade targets that appear to be characterized by high reliability with respect to evolution of hydrodynamic instabilities. 相似文献
20.
S. Dobosz M. Schmidt M. Perdrix P. Meynadier O. Gobert D. Normand K. Ellert T. Blenski A. Ya. Faenov A. I. Magunov T. A. Pikuz I. Yu. Skobelev N. E. Andreev 《Journal of Experimental and Theoretical Physics》1999,88(6):1122-1129
The x-ray spectra of a plasma generated by heating CO2 and Ar clusters with high-intensity femtosecond laser pulses with q
las≃1018 W/cm2 are investigated. Spatially resolved x-ray spectra of a cluster plasma are obtained for the first time. Photoionization absorption
is observed to influence the spectral line profiles. The recorded features of the x-ray emission spectra definitely indicate
the existence of a large relative number of excited ions (≃10−2–10−3) with energies of 0.1–1 MeV in such a plasma. Possible mechanisms underlying the acceleration of ions to high energies are
discussed. It is shown that the experimental results can be attributed to the influence of ponderomotive forces in standing
waves generated by the reflection of laser radiation from the clusters.
Zh. éksp. Teor. Fiz. 115, 2051–2066 (June 1999) 相似文献