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90-nm SRAM memory integrated circuits and CCD- and CMOS-matrices have been irradiated by nucleon beams of the synchrocyclotron at the Konstantinov Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute.” Upset cross section data in memory integrated circuits induced by protons with an energy of 1000 MeV and pixels with large value of dark current (spikes) in optoelectronic devices irradiated by protons with an energy of 1000 MeV and neutrons with an energy spectrum similar to the spectrum of atmospheric neutrons have been presented. Most attention has been paid to the study of spike clusters and multiple upsets occurrence. It has been established that most spikes and single event upsets are located in clusters (multiple upsets).

Energizing current of low-loaded highlycompensated power lines with shunt reactors mainly consists of an aperiodic component, and for a long time has not zerocrossing points. The modern SF6 circuit breaker fails to trip such power line immediately after energizing if unexpected fault or protection relay malfunction occurs because of commutation inability of aperiodic current. This leads to a long arc burning, and eventually to the breaker damage. The paper studies the transients during the commutation of the lowloaded power line and conditions when the amplitude of aperiodic component exceeds a safe level. The study shows that effective prevention of circuit breaker failure may be achieved using controlled switching technology assuming precision control a line energizing moment. The optimal reclosing moment is located near a beat minimum of the circuit breaker voltage and corresponds to the phase of supply voltage, at which the initial amplitude of the energizing current aperiodic component does not exceed the amplitude of the fundamental component. Reclosing of power line at the proposed optimal moment guarantees the safety of commutation for the circuit breaker and ensures mitigation of switching overvoltages.

We study the Callan–Gross ratio R=dσL/dσT in heavy-quark pair leptoproduction, lN→l′QQ¯X, as a probe of linearly polarized gluons inside unpolarized proton, where dσT (dσL) is the differential cross section of the γ⁎N→QQ¯X process initiated by a transverse (longitudinal) virtual photon. Note first that the maximal value for the quantity R allowed by the photon-gluon fusion with unpolarized gluons is large, about 2. We calculate the contribution of the transverse-momentum dependent gluonic counterpart of the Boer–Mulders function, h1⊥g, describing the linear polarization of gluons inside unpolarized proton. Our analysis shows that the maximum value of the ratio R depends strongly on the gluon polarization; it varies from 0 to Q24m2 depending on h1⊥g. We conclude that the Callan–Gross ratio in heavy-quark pair leptoproduction is predicted to be large and very sensitive to the contribution of linearly polarized gluons. For this reason, future measurements of the longitudinal and transverse components of the charm and bottom production cross sections at the proposed EIC and LHeC colliders seem to be very promising for determination of the linear polarization of gluons inside unpolarized proton.

The paper presents the results of studies of the resonance structures of the background electromagnetic noise spectrum obtained in a series of experiments in the autumn of 2012 in Karelia. The experiments are unique because the background noise was detected at stations spaced by a distance much less than the doubled effective waveguide height (about 50 km) in a region close to the main ionospheric trough, the structure and position of which were determined based on radiotomographic data. It is shown that the dimensions of the ionospheric local region, which affects both the generation of spectral resonance structures in particular and the propagation of electromagnetic waves in the considered range in general, depend significantly on the variation of ionospheric parameters in regions with strong horizontal inhomogeneity.

We present the QCD predictions for the azimuthal $\cos 2\varphi$ asymmetry in charm leptoproduction for the kinematics of the COMPASS experiment at CERN. The asymmetry is predicted to be large, about 15%. The radiative corrections to the QCD predictions for the $\cos 2\varphi$ distribution are estimated to be small, less than 10%. Our calculations show that the azimuthal asymmetry in charm production is well defined in pQCD: it is stable both perturbatively and parametrically, and practically insensitive to theoretical uncertainties in the input parameters. We analyze the nonperturbative contributions to the $\cos 2\varphi$ distribution due to the gluon transverse motion in the target and the $c$-quark fragmentation. Because of the $c$-quark low mass, the nonperturbative contributions are expected to be sizable, about (30--40)%. We conclude that extraction of the azimuthal asymmetries from available COMPASS data will provide valuable information about the transverse momentum dependent distribution of the gluon in the proton and the $c$-quark hadronization mechanism. Finally, we discuss the $\cos 2\varphi$ asymmetry as a probe of the gluonic analogue of the Boer-Mulders function, $h_{1}^{\perp g}$, describing the linear polarization of gluons inside unpolarized proton., Comment: 9 pages, 4 figures, LaTeX, journal version

The occurrence of single-event upsets (SEUs) in 90-nm SRAM integrated circuits irradiated by 1000-MeV protons has been investigated. The experimental data were analyzed and processed, and the results showed the possibility of multiple cell upsets in the integrated circuits studied.

We consider the azimuthal $\cos \varphi$ and $\cos 2\varphi$ distributions and the Callan-Gross ratio $R={\rm d}\sigma_L/{\rm d}\sigma_T$ in heavy-quark pair electroproduction, $lN\rightarrow l^{\prime}Q\bar{Q}X$, as probes of linearly polarized gluons in unpolarized nucleons. Our analysis shows that the azimuthal asymmetries and Callan-Gross ratio are predicted to be large and very sensitive to the contribution of the gluonic counterpart of the Boer-Mulders function, $h_{1}^{\perp g}$, describing the linear polarization of gluons inside unpolarized nucleon. In particular, the maximum values of the azimuthal distributions vary from 0 to 1 depending on $h_{1}^{\perp g}$. We conclude that future measurements of these quantities at the proposed EIC and LHeC colliders could clarify in details the proton spin decomposition puzzle., Comment: 4 pages, 4 figures, talk given at the XVIII Workshop on High Energy Spin Physics (DSPIN-19), September 2-6, Dubna

Results of calculations and analysis of the tearing-mode evolution under the effect of resonant magnetic perturbation produced by a nonlinear feedback system in rotating tokamak plasma are presented. The TEAR-code used for calculations is based on the visco-resistive magnetohydrodynamic approximation that gives coupled diffusion-type equations for the magnetic flux perturbation and for the plasma rotation velocities in toroidal and poloidal directions. The code is supplemented by a computational unit simulating the nonlinear algorithm of the feedback system. The feedback gain and phase shift are automatically regulated in real time. The gain depends on the tearing-mode amplitude. At high feedback input signals, the gain does not exceed some finite value to reduce technical requirements for the feedback actuator and to mitigate the phase instability. In the process of the tearing-mode suppression, the gain gradually increases to provide the mode control under reduction of feedback input signal and rise of the intrinsic tearing-mode stability index. Besides that, the real-time control of the feedback phase shift is provided to additionally mitigate the phase instability. According to simulation, the used nonlinear characteristics of the feedback algorithm improve the efficiency of the tearing-mode suppression.

A universal center for testing electronic components (ECs) for the needs of aviation and space is created in the SC-1000 Petersburg Nuclear Physics Institute, National Research Centre “Kurchatov Institute” (PNPI NRC KI). One of the main instruments of these tests is variable energy protons beams. This paper presents Monte Carlo simulation results for a proton beam with energy of 1000 MeV passing through copper and tungsten degraders, and defines the length of these degraders to obtain energies of ~60, 100, 200, 300, 400, 500, 600, 700, 800, 900, and 1000 MeV. Detailed studies of further transmission of the proton beams along the beam line using the copper degrader are accomplished. Basic theoretical parameters for each proton beam, such as the intensity, the energy heterogeneity, beam size, and uniformity of its spatial distribution are obtained.

Results of the experimental study of population inversion in the resonant electronic transition \({B^3}{\pi _g} - {A^3}\sum _u^ + \) of nitrogen ions by optical pumping of atmospheric air and pure nitrogen by a femtosecond laser pulse at a wavelength of 950 nm are presented. It is shown that the inversion results from selective population of the \(N_2^ + \left( {{B^2}\sum _u^ + ,v' = 0} \right)\) excited state during multiphoton excitation of the autoionization state of the nitrogen molecule with an energy of 18.7 eV. Seed photons for superradiance at transitions of molecular nitrogen ions are photons of the axial supercontinuum that occurs in a filament at the corresponding wavelengths. The superradiance mode is implemented at the wavelength λ = 358.4 nm referred to the transition of the CN molecule.

Experimental results on rotation coupling between the m = 2, n = 1 and m = 3, n = 2 tearing-modes in the T-10 tokamak are presented. In the specially chosen T-10 regime, these two modes are observed simultaneously, no modes other than these two ones being detected. For each of the two tearing-modes, a rotation irregularity expressed as frequency modulation is analyzed. The characteristics of the frequency modulation are used to identify the effect of each mode on the oscillations of the other one. According to the experiment, the frequency modulation of each mode consists of two components if the two modes are present simultaneously. The first component is related to the effect of static Error Field and the second one arises due to the mode coupling. For the modes in question with different toroidal numbers, the natural explanation of this coupling is related to the effect of plasma viscosity. The nonlinear visco-resistive TEAR-code is used for simulation and parametric analysis of the experimental data. The simulation results confirm the assumption that the observed coupling between tearing-modes with different toroidal mode-numbers can be attributed to plasma viscosity.

In recent papers [1,2], two new ways have been proposed to probe the linear polarization of gluons in unpolarized proton: using the azimuthal asymmetries and Callan-Gross ratio in heavy-quark pair leptoproduction, $lN\rightarrow l^{\prime}Q\bar{Q}X$. In this talk, we discuss in details the sensitivity of the QCD predictions for the azimuthal $\cos \varphi$ and $\cos 2\varphi$ asymmetries to the contribution of linearly polarized gluons inside unpolarized proton, where the azimuth $\varphi$ is the angle between the lepton scattering plane $(l,l^{\prime})$ and the heavy quark production plane $(N,Q)$. Our analysis shows that the azimuthal distributions under consideration vary from 0 to 1 depending on the transverse-momentum dependent gluonic counterpart of the Boer-Mulders function, $h_{1}^{\perp g}$. We conclude that the $\cos \varphi$ and $\cos 2\varphi$ asymmetries in heavy-quark pair production in DIS processes are predicted to be large in wide kinematic ranges and sensitive to the contribution of linearly polarized gluons., Comment: 6 pages. Contribution to Baldin Seminar ISHEPP XXIV, Dubna, Russia, September 17-22, 2018. arXiv admin note: text overlap with arXiv:1711.05221

We propose a method of cavitating flow calculation that is based on the Eulerian–Lagrangian description of multiphase flows. The formation and growth of cavitation bubbles are described using the model of heterogeneous volume nucleation. Results of test calculations demonstrate the efficiency of the proposed model.

The results of formation conditions studies of a highly directional supercontinuum (SC) in a visible spectrum range obtained upon aberration spherical-mirror focusing of a radiation pulse with a wavelength of 940 nm, duration of 70 fs, and energy of 8–15 mJ are presented. It is shown that after visible filament there are two directed white light beams diverging relative to each other at an angle of 1.4 0 . Formation every light beam occurs through a gradual conversion of the spectral composition from long wavelength to short wavelength (to 350 nm) in a spatially stable structure similar to a soliton with a transverse dimension ≤ 300 μm. The nature of the appearance these beams is due to formation of two zones with higher intensity before meridional plate owing to the distortion of the wavefront of the laser beam in conditions of the astigmatism and the Kerr effect. In result two minima in the phase distribution located outside the beam axis are realized, which lead to the appearance of two off-axis areas with higher radiation intensity and as a consequence of this the formation of two highly directional laser beams.

In this paper, a highly linear complex filter in SOI X-FAB 180 nm technology is proposed for 25 MHz bandwidth with 25 MHz center frequency. Third harmonic compensation technique is used for transconductance amplifier design. Reactance transform is used for the filter synthesis. Layout design is discussed. Simulations show THD better than -75 dB @ 25 MHz 1 Vpp for temperature range of -40 to +200 °C.

The results of calculations and parametric analysis of the plasma rotation reversal subject to the tearing mode under magnetic perturbation of the same helicity are presented. The TEAR code used for the calculations is based on the visco-resistive MHD approximation that gives coupled diffusion-type equations for the magnetic flux perturbation and for the plasma rotation velocities in toroidal and poloidal directions. The resonant magnetic perturbation consists of both the traveling perturbation induced by eddy current in the vacuum vessel and an artificially applied nonrotating magnetic perturbation produced by a current layer outside plasma. The main attention is paid to conditions necessary for the plasma velocity reversals separately in toroidal and poloidal directions, as well as for the concurrent changes of both velocity directions. The dynamics of the plasma toroidal and poloidal rotation-profile variations are also presented.

We study two experimental ways to measure the heavy-quark content of the proton: using the Callan-Gross ratio $R(x,Q^2)=F_L/F_T$ and/or the azimuthal $\cos(2\varphi)$ asymmetry in DIS. Our approach is based on the following observations. First, the ratio $R(x,Q^2)=F_L/F_T$ and azimuthal $\cos(2\varphi)$ asymmetry in heavy-quark leptoproduction are stable, both parametrically and perturbatively, within pQCD. Second, both these quantities are sensitive to resummation of the mass logarithms of the type $\alpha_{s}\ln(Q^{2}/m^{2})$. We conclude that the heavy-quark densities in the nucleon can, in principle, be determined from high-$Q^2$ data on the Callan-Gross ratio and/or the azimuthal asymmetry. In particular, the charm content of the proton can be measured in future studies at the proposed Large Hadron-Electron (LHeC) and Electron-Ion (EIC) Colliders., Comment: 6 pages, 3 figures, talk given at the 20th International Symposium on Spin Physics "Spin 2012", JINR, Dubna, Russia, September 17-22, 2012. arXiv admin note: substantial text overlap with arXiv:1010.5424

Sony ICX 259AL CCD matrices were irradiated by proton and neutron beams of a synchrocyclotron of the Petersburg Nuclear Physics Institute. The data on production cross sections, as well as the spatial and time distributions of pixels of the irradiated matrices with high dark current, are presented. The experimental data are compared with the calculation results.

We study the azimuthal $\cos \varphi$ and $\cos 2\varphi$ asymmetries in heavy-quark pair leptoproduction, $lN\rightarrow l^{\prime}Q\bar{Q}X$, as probes of linearly polarized gluons inside unpolarized proton, where the azimuth $\varphi$ is the angle between the lepton scattering plane $(l,l^{\prime})$ and the heavy quark production plane $(N,Q)$. First, we determine the maximal values for the $\cos \varphi$ and $\cos 2\varphi$ asymmetries allowed by the photon-gluon fusion with unpolarized gluons; these predictions are large, $(\sqrt{3}-1)/2$ and $1/3$, respectively. Then we calculate the contribution of the transverse-momentum dependent gluonic counterpart of the Boer-Mulders function, $h_{1}^{\perp g}$, describing the linear polarization of gluons inside unpolarized proton. Our analysis shows that the maximum values of the azimuthal distributions depend strongly on the gluon polarization; they vary from 0 to 1 depending on $h_{1}^{\perp g}$. We conclude that the azimuthal $\cos \varphi$ and $\cos 2\varphi$ asymmetries in heavy-quark pair leptoproduction are predicted to be large and very sensitive to the contribution of linearly polarized gluons. For this reason, future measurements of the azimuthal distributions in charm and bottom production at the proposed EIC and LHeC colliders seem to be very promising for determination of the linear polarization of gluons inside unpolarized proton., Comment: 10 pages, 6 figures, journal version

The article presents the results of the theoretical and experimental investigation of axial forces arising in the toothed and plate couplings of centrifugal compressor shaft lines. Additional loads on the thrust bearing are considered that can develop in the toothed couplings as a result of coupled rotors misalignment. Design relationships to evaluate the level of axial forces and recommendations for their reduction in the operating conditions are given.

The modeling of the magnetic island evolution under resonant magnetic perturbations, RMP, in rotating ITER-like plasma from seed island initial generation, through appearance and development of the NTM till its locking and saturation is presented. The effects of plasma resistivity, viscosity, diamagnetic drift and the effect of the currents induced in the resistive vacuum vessel wall are taken into account. The calculations are carried out with the TEAR code based on the non-linear modified Rutherford model. The dependence of the tearing mode stability index on the angular position of the mode with respect to the RMP is taken into account. It results in deviations of the magnetic island rotation velocity from the velocity of the plasma layer in the vicinity of the rational magnetic surface. The magnetic island dynamics under RMP is analyzed for the modes originated at the q = 3/2 and q = 2 magnetic surfaces. The NTM behavior is discussed for cases of the seed island generation by different RMP sources including the coils for mitigation of the edge localized modes, ELMs.

We study two experimental ways to measure the heavy-quark content of the proton: using the Callan-Gross ratio $R(x,Q^2)=F_L/F_T$ and/or azimuthal $\cos(2\varphi)$ asymmetry in deep inelastic lepton-nucleon scattering. Our approach is based on the perturbative stability of the QCD predictions for these two quantities. We resume the mass logarithms of the type $\alpha_{s}\ln\left( Q^{2}/m^{2}\right)$ and conclude that heavy-quark densities in the nucleon can, in principle, be determined from data on the Callan-Gross ratio and/or azimuthal asymmetry. In particular, the charm content of the proton can be measured in future studies at the proposed Large Hadron-Electron (LHeC) and Electron-Ion (EIC) Colliders., Comment: 6 pages, 4 figures, revtex. arXiv admin note: substantial text overlap with arXiv:1010.5424, arXiv:1212.3785, arXiv:0812.0722

We use a previously proposed modified saddle point method to describe the tunneling of a rectangular wave packet through a resonant quantum system. We calculate the shape of the wave packet obtained at the quantum system output analytically for different values of the level width. The result of propagation is a wave packet that is the superposition of complementary error functions. Comparing the result with the exact numerical solution obtained without using any asymptotic methods shows a rather good coincidence. We study the propagation of Gaussian and rectangular wave packets in detail for large values of the resonance level width.

The problem of radio radiation source localization is analyzed via the maximum-likelihood method with and without allowance for the polarization of incident waves. It is shown that the direction-finding surface normalization is an important condition. Correct normalization expressions for the time-averaged direction-finding surface have been derived via the nonquadratic regularization method. The numerical simulation results indicate that this method is superior to traditional high-resolution methods in efficiency.

A regularization method for estimating the directions to sources of coherent radio signals was developed which takes into account the vector nature of the electromagnetic field of incident waves and complex radiation patterns of antenna elements and does not depend on the incident wave polarization.

The first results obtained through the university small satellites program developed at Moscow State University (MSU) are presented. The space environment was investigated aboard two MSU microsatellites designed for scientific and educational purposes, Universitetsky-Tat’yana and Universitetsky-Tat’yana-2. The scientific equipment is described to study charged particles in near Earth space and atmospheric radiations in ultraviolet, red, and infrared optical wavelength ranges. The dynamic properties of fluxes of charged particles in microsatellite orbits are studied and findings are presented regarding specific parameters of solar proton penetration during the geomagnetic disturbances. Experimental results are considered concerning flashes of ultraviolet (UV), red (R), and infrared (IR) radiation that are transient light phenomena in the upper atmosphere. The space educational MSU program developed on the basis of the Universitetsky-Tat’yana projects is reviewed.

In the T-10 tokamak, the magnetic field spatially resonant with a helical MHD perturbation is generated using the controlled halo current supplied using a contact method in the scrape-off-layer plasma. This paper is concerned with studying the spatial structure of the halo current and its magnetic field. For this purpose, the magnetic field of the halo current was measured in one of the cross sections of the torus near the tokamak vacuum vessel wall. The spatial distribution of the magnetic field as a function of the halo current configuration was calculated in the cylindrical approximation. The terms proportional to the plasma pressure were disregarded. The configuration of the halo current and the spatial structure of its magnetic field were determined by comparing the calculated and experimental results.

The results of measurements of the artificial electromagnetic signal in the range 0.1–10 Hz on the Spitsbergen archipelago are presented in this paper. The signal was emitted by a horizontal antenna located on the Kola Peninsula. Resonance spectra structures (RSSs) caused by the influence of the ionospheric Alfven resonator (IAR) were found in the artificial signal. The calculations of the field performed using the method of a two-dimensional telegraph equation for an anisotropic inhomogeneous model of the ionosphere allowed us to explain the main properties of the observed artificial RSS signal. Special attention was focused on the choice of the ionospheric model and calculation of the reflection coefficient for a plane wave normally incident on the ionosphere. The needed profiles of the ionospheric parameters were selected on the basis of the Upper Atmosphere Model (UAM) and IRI2007 model, while the atmospheric parameters were specified on the basis of MSIS-E-90. The advantages of the UAM model compared with the IRI for the description of the experimental results in a high-latitude region are shown in the paper.

Different approaches to the problem of estimation of the direction of arrival of the incident wave with an unknown polarization are considered. It is found that the obtained solutions can be used to increase the accuracy and reliability of direction finding due to elimination of polarization errors and to determine the polarization parameters as an additional information parameter. Analysis of the results obtained for a particular configuration of the antenna array is performed. It is shown that the proposed method is more efficient for determination of the direction to the source of an arbitrarily polarized electromagnetic field than the approaches oriented to processing of the field with a predetermined polarization. The results of a numerical simulation confirming these conclusions are presented.

The superconducting and magnetic states of asymmetric ferromagnet/superconductor/ferromagnet (F/S/F′) nanostructures have been investigated using the boundary value problem for the Eilenberger function. It has been shown that 0- and π-phase superconducting states of pure thin F/S/F′ trilayers are controlled by the magnitude and sign of electron correlations in the F and F′ layers, as well as by the competition between homogeneous Bardeen-Cooper-Schrieffer (BCS) pairing and inhomogeneous Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) pairing. The LOFF-BCS-LOFF separate re-entrant superconductivity has been predicted for F/S/F′ trilayers. A continuous control of the pair-breaking factor in the Eilenberger function and transition to the state with re-entrant superconductivity is achieved by varying the thickness of the F′ layer. Sine-modulated 2D LOFF states in asymmetric F/S/F′ trilayers are possible not only for parallel, but also for antiparallel orientations of the magnetizations of the F and F′ layers; this fact significantly facilitates the experimental implementation of the predicted phenomena.

The proximity effect and competition between the BCS and LOFF states are studied in the Cooper limit for thin F/S and F/S/F nanostructures, where F is a ferromagnet and S is a superconductor. The dependences of the critical temperature on the exchange field I, electron correlations λf, and the thickness df of the F layer are derived for F/S bilayers and F/S/F trilayers. In addition, two new π-phase superconducting states with electron-electron repulsion in the F layers of F/S/F trilayers are predicted. A two-dimensional LOFF state in F/S/F trilayers is possible only in the presence of a weak magnetic field and the appropriate parameters of the F and S layers. The absence of the suppression of three-dimensional superconductivity in short-period Gd/La superlattices is explained and the electron-electron coupling constant in gadolinium is predicted. A method of superconducting sounding spectroscopy based on the proximity effect is proposed for determining the symmetry of the order parameter, the magnitude and sign of electron correlations, and the exchange field in various nanomagnets F.

We analyze the Callan–Gross ratio R ( x , Q 2 ) = F L / F T in heavy-quark leptoproduction as a probe of the charm content of the proton. To estimate the charm-initiated contributions, we use the ACOT(χ) variable-flavor-number scheme. Our analysis shows that charm densities of the recent CTEQ sets of parton distributions have sizeable impact on the Callan–Gross ratio in a wide region of x and Q 2 . In particular, the ACOT(χ) predictions for the quantity R ( x , Q 2 ) are about half as large as the corresponding expectations of the photon–gluon fusion mechanism for x ∼ 10 − 2 – 10 − 1 and Q 2 ≫ m 2 . This is because the structure functions F T ( x , Q 2 ) and F L ( x , Q 2 ) have different dependences on the mass logarithms of the type α s ln ( Q 2 / m 2 ) . On the other hand, our recent studies indicate that, contrary to the production cross sections, the Callan–Gross ratio is sufficiently stable under radiative corrections to the photon–gluon fusion component for x ≳ 10 − 4 . We conclude that the quantity R ( x , Q 2 ) in heavy-quark leptoproduction is perturbatively stable but sensitive to resummation of the mass logarithms. For this reason, in contrast to the structure functions, the ratio R ( x , Q 2 ) = F L / F T could be good probe of the charm density in the proton.

The radiation of a bunch of charged particles moving along the axis of a cylindrical waveguide lined with a resonant dispersive dielectric medium is theoretically studied. Conditions necessary for the amplification of generated waveguide modes are established. It is shown that any selected mode or a group of neighboring modes can be amplified provided that the system parameters are properly chosen. The maximum possible growth increment is independent of the mode number and is determined entirely by the properties of the resonant medium.

We analyze the perturbative and parametric stability of the QCD predictions for the azimuthal asymmetries in heavy quark leptoproduction. At leading order, the $\cos \phi$ asymmetry vanishes whereas the $\cos 2\phi$ one is of leading twist and predicted to be about 15% at energies sufficiently above the production threshold. We calculate the NLO soft-gluon corrections to $\phi$-dependent leptoproduction to the next-to-leading logarithmic accuracy. The soft-gluon approximation provides a good description of the available exact NLO results at $Q^{2}\lesssim m^{2}$. Our analysis shows that, contrary to the production cross sections, the $\cos 2\phi$ asymmetry is practically insensitive to soft radiation for $Q^{2}\lesssim m^{2}$ at energies of the fixed target experiments. We conclude that the $\cos 2\phi$ asymmetry is well defined in pQCD: it is stable both perturbatively and parametrically, and insensitive (in the case of bottom production) to nonperturbative contributions. Measurements of the azimuthal asymmetries would provide an excellent test of pQCD applicability to heavy flavor production., Comment: 13 pages, 9 figures, revtex, minor corrections, to appear in Nucl.Phys.B

Anisotropic electron heating during the absorption of a strong high-frequency field due to electronion collisions is studied numerically by a Monte Carlo method. The electron distribution that forms in a strong high-frequency field under the action of electron-electron and electron-ion collisions is shown to be close to a bi-Maxwellian anisotropic velocity distribution. The extent to which the electron heating lowers the generation efficiency of the higher harmonics is determined.

For the first time, data from eight different tokamaks have been combined in an international database for internal transport barriers (ITBs). An analysis of the data for the formation of an ITB with dominant ion heating shows a clear dependence of the threshold power on the minor radius and line-averaged electron density for the formation of ion ITBs. The dependence of ITB formation on the toroidal magnetic field is weak. For the formation of ITBs with dominant electron heating, the database is smaller, but for the threshold power a strong increase with plasma size and a weak toroidal field dependence could also be identified. Based on these results, an expression for the power required to form an ITB is given using global variables only. These results give a basis for the analysis of the database using local values (like magnetic shear) and a detailed comparison with theory-based models.

Results of simulation and parametric analysis of magnetic island production by helical magnetic perturbation generated under non-axisymmetric halo current are presented. Predictions are made for a cylindrical ITER-size plasma in conditions of disruption. Calculations are carried out with the TEAR code based on the visco-resistive MHD approximation. The radial distribution of the magnetic flux perturbation is calculated with account of the external helical field produced by halo current. The equations for the magnetic flux perturbation describe the dynamics of the tearing mode depending on plasma rotation. In sequence, this rotation is affected by electromagnetic forces depending on the tearing mode magnetic field and external magnetic perturbation. The coupled diffusion-type equations for the helical flux function and for the plasma rotation velocity are numerically treated in a similar way. The magnetic island behavior is analyzed for different plasma parameters expected at the Current Quench stage of di...

Tunneling of wave packages through resonant quantum systems presented in an S-matrix form is investigated. An arbitrary incident wave package can be written as the superposition of the Gaussian-form pulses and for latter ones the exact analytic solution was obtained already. As a practically interesting case, the transition of the rectangular wave package through a one-resonant level system is considered. Using developed recently modified saddle-points method the transition of the wave package having a Gaussian and a rectangular form is investigated. The time delay, argument and amplitude of the outgoing wave are calculated. The dependence of tunneling time on the width and energy of resonance levels, and the momentum of incident wave-package are illustrated. The results are compared with the ones obtained for tunneling of the one Gaussian package. Possible applications are discussed.

The influence of kinetic effects on the generation of line X radiation during the spherical implosion of a laser corona plasma with two ion species is studied under the conditions prevailing in experiments with thin-wall spherical targets in the Iskra-5 laser facility of the All-Russia Research Institute of Experimental Physics (Sarov, Russia). Kinetic processes occurring in a multicharged plasma are investigated using a specially devised code for solving one-dimensional Landau equations for a nondegenerate multicomponent plasma by the Monte Carlo method (the KIN-MC code). The code was developed using the quasineutral plasma approximation under the assumption that the electron distribution function is locally equilibrium. The model equations are presented, the scheme of numerical solution is described, and the calculated results are discussed.

The results of investigations of the divergence of an amplified diffracted beam of diameter from 1.5 to 150 mm produced by a XeCl laser are presented. It has been shown that if the intensity distribution of the amplified radiation is spatially nonuniform, the wave front in the active medium changes substantially due to the diffraction of the radiation at a small-diameter diaphragm. The active medium of the amplifier excited by an electron beam makes it possible to amplify without visible distortions a laser beam with a divergence of ≈10 μrad.

The behaviour of relative content of one-fold neutrons in the incident flux of cosmic rays during Forbush-decreases and solar cosmic ray flares is considered based on the network of cosmic ray stations. The barometric dependence of this value on the network of cosmic ray stations. The barometric dependence of this value on the latitude and see level altitude of a cosmic ray station is obtained.

Ion interpenetration, stagnation, and energization processes are studied in colliding laser‐produced plasma configurations relevant to Trident [R. G. Watt, Rev. Sci. Instrum. 64, 1770 (1993)] experiments using four different numerical methods: one‐dimensional Monte Carlo and Lagrangian multifluid codes, and one‐ and two‐dimensional hybrid (particle ions, fluid electrons) and single‐fluid Lagrangian codes. Results from the four methodologies are compared for plasmas generated with gold and deuterated polyethylene (CD2) targets. Overall, the various codes give similar results concerning the initial expansion of the plasmas and their collisional interaction, the degree of stagnation, stagnation time, and amount of ion thermalization for gold targets, while multispecies techniques indicate a much softer stagnation for CD2 plasmas than the single‐fluid model. Variations in the results of the calculations due to somewhat different initializations and parameters, as well as to different physics in the codes, are discussed.

A comparative study of the methods of interpretation of solvent influences on electric properties of molecules was conducted based on experimental dielectric properties of dilute solutions of organic substances of various polarity. It was shown that the solvent effect estimated via London—Debye—Keesom pairwise interaction potentials is best accounted for by theories of polarization of condense media which develop the anzatzes of reactive field and local dielectric permittivity.

A generalization of the quark-gluon string model to the case of bosonic resonances production in hadron-hadron collisions is proposed. In the framework of our approach, the properties of the fragmentation functions of quarks and diquarks are determined on the basis of the reggeon-photon analogy. As a result, we obtain a simple relation which determines the dependence of the production cross sections on the spinJ of observed resonances. It is shown that the theoretical predictions are confirmed experimentally with a good accuracy in both inclusive and binary processes.

The deconvolution method, i.e., reconstruction of noise-free discrete amplitude distributions of excitatory postsynaptic potentials (EPSPs), has been tested in computer experiments. A “generalized quantal model” without constraints on distribution of transmitter release probabilities (p) was used. Complex binomial amplitude distributions with a number of discrete components n between 2 and 10 and with different p were simulated. The distance between the discrete components (i.e., the quantum value, v) was determined from simulated distributions with the number of amplitudes N equal to 1000 or 100. For samples with N=100, mean v values were calculated from 10 distributions. The solutions obtained by deconvolution were close to (within ±20% of) the simulated v values when the standard deviation of the noise Sn≤0.5v. For Sn=0.5−2.0v, v grew in proportion to Sn and was overestimated. A similar correlation was found for v calculated from amplitudes of minimal EPSPs recorded from CA1 area neurons of guinea pig hippocampal slices. However, no significant correlation between v and Sn was found for v>135 µV, i.e., for estimates exceeding the total mean value. A substantial increase in the mean quantal content (m) with a relatively slight increase in v during longterm potentiation (LTP) was confirmed for those cases. Methods of elimination of erroneous v estimates were considered. Rejection of cases with v>2.5Sn (when N=1000) or v>3Sn (when N=100) eliminated erroneous estimates with a high probability but demanded very low noise levels. A new criterion for recognition of correct estimates is suggested. It is based on artificial “contamination” of the measured amplitudes by the Gaussian noise (noise addition) and on the double-step dependence of v on Sn described above. The solutions selected with this criterion also support a predominant increase of m during LTP with a slight growth of v.

We study two experimental ways to measure the heavy-quark content of the proton: using the Callan-Gross ratio $R(x,Q^2)=F_L/F_T$ and/or the azimuthal $\cos(2\phi)$ asymmetry in deep inelastic lepton-nucleon scattering. Our approach is based on the following observations. First, unlike the production cross sections, the ratio $R(x,Q^2)=F_L/F_T$ and the azimuthal $\cos(2\phi)$ asymmetry in heavy-quark leptoproduction are sufficiently stable, both parametricallly and perturbatively, in a wide region of variables $x$ and $Q^2$ within the fixed-flavor-number scheme of QCD. Second, both these quantities, $R(x,Q^2)=F_L/F_T$ and $\cos(2\phi)$ asymmetry, are sensitive to resummation of the mass logarithms of the type $\alpha_{s}\ln\left(Q^{2}/m^{2}\right)$ within the variable-flavor-number schemes. These two facts together imply that the heavy-quark densities in the nucleon can, in principle, be determined from high-$Q^2$ data on the Callan-Gross ratio and/or the azimuthal asymmetry in heavy-quark leptoproduction. In particular, the charm content of the proton can be measured in future studies at the proposed Large Hadron-Electron (LHeC) and Electron-Ion (EIC) Colliders., Comment: 9 pages, 4 figures, LaTeX. Talk given at the Workshop on Exclusive Reactions at High Momentum Transfer (IV), May 18-21, 2010, TJNAF, Newport News, VA and Electron-Ion Collider Collaboration Meeting, July 29-31, 2010, Catholic University of America, Washington, DC

Excitatory postsynaptic potentials (EPSPs) evoked by near-threshold stimulation of the radial layer were recorded from the CA1 area of guinea pig hippocampal slices. An optimization method based on the deconvolution technique was used to reconstruct a “noise-free” discrete distribution of the amplitudes with regular (“quantal”) intervals (v) between the discrete components. The standard deviation of v (Sv) was studied for its effect on the estimate of the v value. Twenty-two amplitude distributions with approximately regular, visually distinguishable peaks were analyzed. It was found that, in some cases, too small ( 0.3–0.4 v) Sv led to lower v estimates in comparison with those obtained for Sv in the range of 0.1–0.3 v. Computer experiments have shown that too small or too large Sv values may lead to underestimates of the stimulated v values. The average underestimate for physiological data is probably 10–15%, but, in some cases, it may be higher. Judging from a maximal verisimilitude criterion, optimal v estimates are obtained for Sv between 0 and 0.15 v. Comparison of simulated and physiological data suggests that the variation coefficient of v for hippocampal synapses formed by radial fibers on CA1 neurons is equal to 0.1–0.2 Sv values generally accepted for the deconvolution procedure (0 or 0.05 v) seem to be underestimated for central synapses, while Sv>0.3 v are overestimated. Underestimates of Sv known from literature may be due to a dependence of the deconvolution procedure results on the noise level, as well as due to a probable nonlinear interaction between the signal and noise. Overestimates may be a result of multiple spontaneous quantal release.

We analyze the perturbative and parametric stability of the QCD predictions for the Callan-Gross ratio $R(x,Q^2)=F_L/F_T$ in heavy-quark leptoproduction. We consider the radiative corrections to the dominant photon-gluon fusion mechanism. In various kinematic regions, the following contributions are investigated: exact NLO results at low and moderate $Q^2\lesssim m^2$, asymptotic NLO predictions at high $Q^2\gg m^2$, and both NLO and NNLO soft-gluon (or threshold) corrections at large Bjorken $x$. Our analysis shows that large radiative corrections to the structure functions $F_T(x,Q^2)$ and $F_L(x,Q^2)$ cancel each other in their ratio $R(x,Q^2)$ with good accuracy. As a result, the NLO contributions to the Callan-Gross ratio are less than 10% in a wide region of the variables $x$ and $Q^2$. We provide compact LO predictions for $R(x,Q^2)$ in the case of low $x\ll 1$. A simple formula connecting the high-energy behavior of the Callan-Gross ratio and low-$x$ asymptotics of the gluon density is derived. It is shown that the obtained hadron-level predictions for $R(x\to 0,Q^2)$ are stable under the DGLAP evolution of the gluon distribution function. Our analytic results simplify the extraction of the structure functions $F_2^c(x,Q^2)$ and $F_2^b(x,Q^2)$ from measurements of the corresponding reduced cross sections, in particular at DESY HERA., 14 pages, 6 figures, revtex4; minor corrections

A theoretical analysis of the inclusive production ofp-mesons in πN-collisions is carried out. It is shown that the reggeized pion exchange mechanism describes well a large set of the experimental data in the region of the Feynman variablex>0.6. The combination with the model of quark-gluon strings leads to a good agreement with the experiment for allx. The inclusive production of high spin resonances is discussed.