P.G. Krytikov , A.I. Nikishov , V.I. Ritus , V.I. Sergienko
№ 11 FEASIBILITY OF EXPERIMENTAL INVESTIGATION OF NONLINEAR QED PROCESSES — PHOTON EMISSION BY ELECTRONS AND PAIR CREATION BY PHOTONS IN STRONG LASER FIELD
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On the basis of the theory of nonlinear QED processes occurring in collisions of high energy electrons and 7-quanta with strong laser pulse [1] the feasibility of their experimental investigation is discussed. The employment of existent 100 GeV electron beam accelerators and terawatt lasers of ultrashort pulses enables to attain optimal values for the parameters and to aot on electron by the field = FQ — vrc^/tie. The choice and organization of laser system, synchronization of accelerator and laser operation, distributions of created 7-quanta and e+e—pairs in different variables and parameters, their dependence on polarization of laser target and Incident particles, background problems and other questions connected with carrying out the experiments are discussed.
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A.Garry. Sokol
№ 14 SI-MICRO STRIP DETECTOR WITH INTRINSIC AMPLIFICATION.
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A.B. Ryzkov , A.G. Savinkov , I.S. Shapiro
№ 15 Topological charges and P-parity nonconservation
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It is emphasized that for a variety of quantum systems possessing topological charges the P-parity of the wave function can not be de?fined. The only acceptable representation of the space inversion for such objects is a CP-type transformation. Conserning the latter fea?ture a speculation on possible interconnection between CP-violation and topological charge nonconservation is presented. Some related observable phenomena are pointed out.
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I.G. Lebo , V.B. Rozanov , V.F. Tishkin
№ 22 HYDRODYNAMIC INSTABILITY AND TARGET DESIGN
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The results of a theoretical analysis and numerical simulation of a developing hydrodynamic instability in a laser target are reported The calculations were performed with the help of a 2D Lagrange code «ATLANT». The heating and compression of shells performed with the help of lasers on an experimental setup «DELFIN-1» (ПАЮ were numerically simulated. The conditions of the target irradiation asymmetry were calculated in frames of the approach published in [1]. Figures 1 and 2 illustrate the main equations which had been solved by means of the difference methods. Figure 3 demonstrates formulation of the problem and gives the calculation results. In the absence of the laser flux perturbations ^case ID) the collapse time is tc=5.26 ns, convergent ratio ?=40, and the neutron yield 2-l(r. By reaching the laser flux perturbations with the amplitude 25% and the spherical harmonics n=4 С q (АЛ) = 0)the shell collapsed before reaching the center. The neutron yield was 2-lCr. A series of calculations has been made with the
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V.M. Kolybasov , D.V. Voronov
№ 29 Additional test of the role of pion-nucleon rescattering in pd- annihilation
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Distribution of invariant mass of 7rp system is investigated as the additional test of reaction mechanism for most interesting channel of stopped antiproton annihilation on deuterium pd — PS2П+3П- . It is shown that distinct Д- resonance peak must be seen for events with spectator proton momenta above 200 MеV/c.
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I.G. Lebo , V.B. Rozanov
№ 32 RAYLEIGH-TAYLOR INSTABILITY IN THE INCOMPRESSIBLE SHELL WITH ALLOWANCE FOR ABLATIVE STABILIZATION
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The equations describing the evolution of small perturbations of the boundary incompressible fluid spherical shells with allowance for ablative effect are obtained. A system of ordinary differential equations describes the behaviour of shell boundary perturbations СД( on the inner boundary of the shell and Aa on the outer boundary). This model takes into account an ablation effect and the influence of outer pressure perturbation in accordance with the technique suggested in 11,21). In order to take into account the influence of laser target corona we used the approximation of quaslstationary plasma expansion. Generally, the equation system -is solved numerically. We obtained the solutions describing the ablative stabilization effect in such targets.
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Yu.S. Kas»yanov , G.S. Sarkisov
№ 35 SPATIAL-TEMPORAL MEASUREMENTS OF MAGNETIC FIELDS IN LASER-PRODUCED PLASMAS.
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The results of investigation of the electromagnetic nave polarization, probing high temperature laser plasma as welL as spatial-temporal structure of the magnetic fields, elec?tron density, current density and electron drift velocity are presented. To create plasma the plane massive Al targets were irradiated with second harmonic Nd-laser «FENIKS» under intensities up to 5* 10**W/cm2, It was shown that the magne-tooptical Faraday effect is the main mechanism, that is res?ponsible for changing polarization of the probing wave. Mag?netic fields up to 0,4MG with electron densities ~10гост-3 were measured. Analysis of the magnetic fields spatial dis?tribution gave that the current density achieved the value -~9OMA/cm2 on the. laser axis. Radial structure of the magne?tic field testified to availability reversed current in the laser plasma. The spatial and temporal resolutions in these experiments were equals to ~5ткт and ~5Ops respectively.
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I.G. Lebo , I.V. Popov , V.B. Rozanov , K.. Rohlena , V.F. Tishkin
№ 38 THE RESULTS OF 2D NUMERICAL SIMUUTIONS OF SUBNANOSECOND IODINE LASER INTERACTION WITH AN AL FOIL TARGET
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This report presents the results of theoretical study and 2D numerical simulations of subnanosecond iodine laser pulses interaction with an Airfoil target. The target arid laser parameters correspond to the experimental conditions of «PERUN» iodine laser facility (IP, Prague: pulse energy < 50 J, * 300 ps, focal spot d * 100 fjm; target: Al foil thickness 30 цт). The simulations were made by using two-dimensional Lagrange code "ATLANT" CFIAN-IMM, Moscow). We varied the diameter of focal spot and studied dependence of plasma parameters (temperature. X-ray yield etc.) on laser flux density and diameter of focal spots. The numerical results were compared with experimental data.
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V.G. Bakaev , G.E. Metreveli , G.V. Sychugov , A.D. Vadkovskii , V.D. Zvorykin
№ 39 HIGH-POWER ELECTRON-BEAM-PUMPED КгF LASER WITH INJECTION-CONTROLLED NARROW-BAND TUNABLE OUTPUT
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A high-power KrP laser system based on a wide-aperture electron-beam pumped exoimer laser «GAEPUN» with .injection-looking from a disoharge pumped narrow-band oeoillator has been derelopeL The laser radiation spectral brightness of «. 5 x 10″ W/лп srad cm with narrow linewidth ~ 0.1 cm» tunable near X- 2AQ mn, ani t!:.e output peak porer of ? 1 OH have been obtained.
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K.V. Mitsen , O.M. Ivanenko
№ 40 Peculiarities of HTSC properties as evidence of specific electron spectrum
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The distinctive feature of HTSC electron spectrum is supposed to be the localized pair orbital with single-particle energy level placed at the top of oxygen valence band. Due to pinning of chemical potential at the pair level the hole carrier distribution turns out to be nondegenerated that results in predominance of hole-hole scattering in relaxation processes. The experimental temperature and frequency dependencies of dc and optical conductivities may be explained in the context of this model. It is shown that free exchange of electrons between band and localized pair states on «negative-U centers» may result in the first-order superconducting phase transition without latent heat. The various experimental results on HTSC are found to be in agreement with such feature of superconducting transition.
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O.M. Ivanenko , K.V. Mitsen
№ 41 Modification of electron spectrum and properties of HTSC with doping
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The mechanism of doping influence on electron spectrum of La2.xSrxCuC>4 and Nd2-xCexCu04 is proposed. In the frames of simple model taking into account the local nature of HTSC electron properties the appearance of «midgap states» and the existence of critical concentration values (0.15 and 0.25) are explained. The effect of doping-induced changes of electron structure on transport and superconducting properties of La2-xSrxCu04 and Nd2-xCexCu04 is considered. The dependence of Hall resistance on doping concentration x is discussed. It is shown that in Nd2-xCexCu04 just at x=0.15 the pair level of «negative-U centers» arises at the top of valence band and the dielectric-metal transition takes place. The superconductivity in Nd2-xCexCu04 occurs in hole-conductive phase.
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O.D. Dalkarov , A.Yu. Voronin
№ 42 ON THE POSSIBLE MECHANISM OF THE ANTIPRO1ON0EIAYED ANNIHILATION IN THE LIGHT ATOMS.
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We treat the antiproton delayed annihilation in p He in terms of unitary coupled channels model. The lifetime of antiprotons in p Li is predicted to be of order of 10-7 s, while the corresponding fraction of delayed antiprotons in Li is predicted to be about 1%.
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Yu.I. Belov , Yu.P. Ilyasov , B.A. Poperechenko , V.V. Oreshko , O.V. Doroshenko
№ 50 The first results of millisecond pulsar timing by 64-m-diameter reflector radio telescope TNA-1500 in Russia
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Timing observations of the millisecond pulsar 1937+21 are begining at 610 MHz by means of radio telescope TNA-1500 with 64-m full steerable antenna at «Med-vezh’y Ozera» (Bear Lckes) Radio Observatory of the Special Research Bureau of the Moscow Power Engineer?ing Institute not so far from Moscow. A 40-channeb filter bank receiver of the bandwidth 1.6 MHz and data acqui?sition system controlled by computer PC AT-286/287 are used now in the timing observations. The total noise tem?perature is about 160 K. The signal/noise ratio is about 50 for 30 min time integration. RMS of the TOA mea-, surement (time of arrival) is about 400 ns. The PSR . 1937+21 timing data will be used for generation of the Pulsar Time Scale complementary with the data obtained from timing observations of the reference «normal» pul?sars PSR 0834+06 and PSR 1919+21 at the Pushcliino Radio Observatory of the P.N. Lebedev Physical Institute for more than 13-yrs time interval.
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