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On the asteroid-comet hazard mitigation problem for the earth

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Journal of Harbin institute of Technology(New Series) 2003年第4期10卷 358-362页

作者： V V Ivashkin M V keldysh institute of Applied Mathematics

In frame of the asteroid-comet hazard problem study, a qualitative analysis of some methods for the effect on a celestial near-Earth object (NEO)-an asteroid, a comet — is carried out. The goal of the effect is a correction of this object’s orbit, its deflection from the Earth to prevent their collision. There are studied a mechanical impact-kinetic effect of the spacecraft (SC), a thermonuclear effect, an effect on a cometary nucleus for a controlled change of its dusty mantle and, therefore, its sublimation activity. Qualitative models of these effects are developed. Numerical analysis results are given for a group of NEOs such as some asteroids from the Apollo family (Apollo, Castalia, Nereus, Orpheus, Phaethon, Toutatis, etc.) and from the Aten family (Aten, Hathor, Khufu, etc.) as well as some short-periodic comets like the comet P/Biela. There are studied some characteristics of the effects on the NEOs such as the velocity impulse (or acceleration) applied to the celestial body, its deflection from the Earth. The study is supported by the Russian Foundation of Basic Studies (Grant N 01-01-00133).

关键词： hazard mitigation asteroid-comet hazard impact-kinetic effect

Numerical method for simulating rarefaction shocks in the approximation of phase-flip hydrodynamics

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Applied Mathematics and Mechanics(English Edition) 2021年第6期42卷 871-884页

作者： M.M.BASKO keldysh institute of Applied Mathematics Russian Academy of SciencesMiusskaya Square 4Moscow 125047Russia

A finite-difference algorithm is proposed for numerical modeling of hydrodynamic flows with rarefaction shocks, in which the fluid undergoes a jump-like liquid-gas phase transition. This new type of flow discontinuity, unexplored so far in computational fluid dynamics, arises in the approximation of phase-flip(PF) hydrodynamics, where a highly dynamic fluid is allowed to reach the innermost limit of metastability at the spinodal, upon which an instantaneous relaxation to the full phase equilibrium(EQ) is assumed. A new element in the proposed method is artificial kinetics of the phase transition, represented by an artificial relaxation term in the energy equation for a "hidden"component of the internal energy, temporarily withdrawn from the fluid at the moment of the PF transition. When combined with an appropriate variant of artificial viscosity in the Lagrangian framework, the latter ensures convergence to exact discontinuous solutions, which is demonstrated with several test cases.

关键词： fluid dynamics with phase transitions two-phase flow rarefaction shock Lagrangian scheme artificial viscosity artificial kinetics

Influence of the safety factor profile on the particle and heat transport in the Globus-M spherical tokamak

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Plasma Science and Technology 2019年第11期21卷 1-6页

作者： A YU TELNOVA G S KURSKIEV E O KISELEV N N BAKHAREV V K GUSEV N A KHROMOV S YU MEDVEDEV V B MIINAEV I V MIROSHNIKOV M I PATROV Yu V PETROV N V SAKHAROV A D SLADKOMEDOVA P B SHCHEGOLEV V V SOLOKHA V A TOKAREV S YU TOLSTYAKOV E A TUKHMENEVA Ioffe institute Saint-Petersburg 194021Russia keldysh institute Russian Academy of SciencesMoscow 125047Russia NRC'Kurchatov institute’ Moscow 123098Russia

The advanced tokamak scenario is a promising operation scenario for ITER and fusion neutron *** this scenario the minimum value of the safety factor in the center of the plasma exceeds *** the compact spherical tokamak Globus-M,the formation of such conditions is possible with neutral beam injection at the current ramp-up *** to the slower diffusion of current inside the plasma,a zone is formed with reduced heat and particle transport across the magnetic field,which affects the temperature and density profiles of the *** leads to the peaked density profile formation and improvement of the energy confinement *** achieve a high fraction of the bootstrap current,it is necessary to increase the plasma *** the same time,the maximum allowable pressure is limited to the normalized beta limit.

关键词： advanced tokamak mode transport analysis internal transport barriers

Extreme matter compression caused by radiation cooling effect in gigabar shock wave driven by laser-accelerated fast electrons

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Matter and Radiation at Extremes 2021年第2期6卷 1-7页

作者： S.Yu.Gus’kov P.A.Kuchugov G.A.Vergunova P.N.Lebedev Physical institute of the Russian Academy of Sciences MoscowRussia keldysh institute of Applied Mathematics of the Russian Academy of Sciences MoscowRussia

Heating a solid material with laser-accelerated fast electrons is a particularly useful method for generating a plane powerful shock wave with a pressure of several hundred or even thousands of Mbar in the *** the front of such a powerful shock wave,dense plasma is heated to a temperature of several ***,a high rate of radiation energy loss occurs even in low-Z *** this paper,the strong compression of matter due to radiation cooling in a Gbar shock wave driven by fast electrons is studied using both computational and theoretical *** is shown that the effect of radiation cooling leads to compression of matter in the peripheral region of the shock wave to a density several times greater than the density at its *** a solid material by a petawatt flux of laser-accelerated fast electrons offers the opportunity to surpass the gigabar pressure level of plane shock waves generated by the impact of laser-accelerated *** pressures of about 100 Gbar can be achieved under laboratory conditions only when a spherical target is imploded under the action of a terawatt laser pulse.

关键词： laser shock wave

PARAMETRIC OPTIMIZING ANALYSIS OF UNSTEADY STRUCTURES AND VISUALIZATION OF MULTIDIMENSIONAL DATA

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International Journal of Modeling, Simulation, and Scientific Computing 2013年第S01期4卷 115-127页

作者： A.E.BONDAREV V.A.GALAKTIONOV Computer Graphics Department keldysh institute for Applied Mathematics Russian Academy of Sciences Moscow 125047Russia

The paper presents an approach to fast approximate estimation of conditions for spacetime structures appearing in the *** approach is based on combination of optimization problem computation with methods of data visual *** visual presentation methods are applied for analysis of multidimensional array containing discrete result *** problem solution is implemented by parallel computation in a multitask *** some cases,the approach allows to obtain for control parameter of considered problem the sought-for approximate dependence on characteristic parameters in a quasi-analytical form.

关键词： Optimization visualization parallel computations.

On the Solution Accuracy Downstream of Shocks When Using Godunov-Type *** of Errors in One-Dimensional Problems

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Communications in Computational Physics 2023年第8期34卷 749-786页

作者： Alexander V.Rodionov keldysh institute of Applied Mathematics Russian Academy of SciencesMoscow125047Russia RFNC–All-Russian Scientific Research institute of Experimental Physics Sarov607188Russia

The article opens a series of publications devoted to a systematic study of numerical errors behind the shock wave when using high-order Godunov-type schemes,including in combination with the artificial viscosity *** proposed paper describes the numerical methods used in the study,and identifies the main factors affecting the accuracy of the solution for the case of one-dimensional gas dynamic *** physical interpretation of the identified factors is given and their influence on the grid convergence is analyzed.

关键词： Shock-capturing methods Riemann problem WENO reconstruction Runge-Kutta method Hancock-Rodionov method artificial viscosity approach Shu-Osher test problem

Radial density profile and stability of capillary discharge plasma waveguides of lengths up to 40 cm

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High Power Laser Science and Engineering 2021年第2期9卷 31-40页

作者： M.Turner A.J.Gonsalves S.S.Bulanov C.Benedetti N.A.Bobrova V.A.Gasilov P.V.Sasorov G.Korn K.Nakamura J.van Tilborg C.G.Geddes C.B.Schroeder E.Esarey Lawrence Berkeley National Laboratory BerkeleyCAUSA keldysh institute of Applied Mathematics RAS MoscowRussia ELI Beamlines DolníBˇrežanyCzech Republic

We measured the parameter reproducibility and radial electron density profile of capillary discharge waveguides with diameters of 650µm to 2 mm and lengths of 9 to 40 *** the best of the authors’knowledge,40 cm is the longest discharge capillary plasma waveguide to *** length is important for≥10 GeV electron energy gain in a single laser-driven plasma wakefield acceleration *** of waveguide parameter variations showed that their focusing strength was stable and reproducible to<0.2%and their average on-axis plasma electron density to<1%.These variations explain only a small fraction of laser-driven plasma wakefield acceleration electron bunch variations observed in experiments to *** of laser pulse centroid oscillations revealed that the radial channel profile rises faster than parabolic and is in excellent agreement with magnetohydrodynamic simulation *** show that the effects of non-parabolic contributions on Gaussian pulse propagation were negligible when the pulse was approximately matched to the ***,they affected pulse propagation for a non-matched configuration in which the waveguide was used as a plasma telescope to change the focused laser pulse spot size.

关键词： capillary plasma waveguide laser-driven plasma wakefield acceleration plasma telescope matched laser guiding

Laser-induced liquid tin discharge plasma and its EUV spectra

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Chinese Optics Letters 2020年第5期18卷 40-43页

作者： Junwu Wang Xinbing Wang Duluo Zuo Vassily Zakharov Wuhan National Research Center for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China keldysh institute of Applied Mathematics Russian Academy of SciencesMoscow 125047Russia

Laser-induced discharge plasmas(LDPs) have the potential to be inspection and metrology sources in extreme ultraviolet(EUV) lithography. An LDP EUV source was developed to avoid tin electrode erosion in which a tin pool was used as a cathode. A CO2 pulse laser was focused on the liquid tin target surface, and then a breakdown occurred in a very short time. The voltage-current characteristics of the discharge oscillated, lasting for several microseconds, and an RLC fitting model was used to obtain the inductance and resistance. An intensified chargecoupled device(ICCD) camera was used to investigate the dynamics of LDP, which can explain the formation of a discharge channel. The EUV spectra of laser-induced liquid tin discharge plasma were detected by a grazing incident ultraviolet spectrometer, compared with a laser-produced tin droplet plasma EUV spectrum. To explain the EUV spectrum difference of laser-induced liquid tin discharge plasma and laser-produced tin droplet plasma,the collision radiation(CR) model combined with COWAN code was used to fit the experimental EUV spectrum, which can estimate the electron temperature and density of the plasma.

关键词： laser induced discharge plasma voltage-current characteristics liquid tin plasma plume extreme ultraviolet spectra

大功率离子推力器和流动控制单元验证现状及其2000小时寿命试验（英文）

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推进技术 2020年第1期41卷 109-120页

作者： Alexander S Lovtsov Michael Y Selivanov Andrey N Kostin Andrey A Shagayda keldysh Research Center

为了发展基于电推进的大功率空间运输系统,需要开发和验证功率达数十千瓦的电推进系统,深空任务电推进系统优化的比冲要求高达105s。凯尔迪什研究中心(KeRC)正在开发这样的电推进部件。本文概述了35kW离子推力器IT-500及其流动单元FCU-... 详细信息

为了发展基于电推进的大功率空间运输系统,需要开发和验证功率达数十千瓦的电推进系统,深空任务电推进系统优化的比冲要求高达105s。凯尔迪什研究中心(KeRC)正在开发这样的电推进部件。本文概述了35kW离子推力器IT-500及其流动单元FCU-500的验证现状。作为其验证的一部分,完成了IT-500和FCU-500的2000h寿命试验。其中,离子推力器大部分验证条件是:输入功率17.8kW,使用了40kg氙,2018h寿命试验。本文介绍了磁场和离子光学以及石墨格栅开发现状。

关键词：离子推力器大功率放电室离子光学