MDP-SOCC PROGRAM FOR SOLVING MOLECULAR-DYNAMICS PROBLEMS ON PARALLEL COMPUTERS WITH DISTRIBUTED MEMORY

A.Yu. Aleinikov, R.A. Barabanov, O.I. Butnev, A.N. Bykov, R.A. Veselov, B.L. Voronin, N.S. Ganchuk, V.I. Delov, A.M. Erofeev, V.A. Pronin, N.M. Rud'ko, A.A. Selezenev, S.I. Skrypnik
VANT. Ser.: Mat. Mod. Fiz. Proc. 2001. No 1. P. 3-13.

Basic physical and mathematical concepts of a molecular-dynamics method is presented. A description is given of the strategy for developing a program to solve problems on parallel computers with distributed memory using this method. The paper presents the results of the test calculations on SOCC1 cluster, which consists of 16 nodes connected by a Giganet switch (each node contained two processors Pentium II with the clock frequency of 450 MHz), as well as on some U.S. parallel computer systems.

V.E. Neuvazhayev, A.F. Podkorytova
VANT. Ser.: Mat. Mod. Fiz. Proc. 2001. No 1. P. 14-19.

Turbulent mixing of a thin layer of a fluid with the density r⁰ and width L₀ placed into the medium with the density r, which occurs under the influence of accelerated motion of a container (s = ттgdt, g is the acceleration, s is the motion) is considered in the papers by S.Z. Belenky and E.S. Fradkin (1965) and in the paper by V.E. Neuvazhayev. In the paper by V.E. Neuvazhaev the formula of the asymptotic stage was obtained, where L is the width of a turbulent mixing zone. In this paper the generalities of mixing process approach to a self-similar mode are investigated using the TURINB program (ke -model). It is stated that the coefficient b, describing the turbulent mixing at the self-similar stage is universal and independent of densities change. In the case of a thin heavy layer however the approach to the self-similar mode takes place later at the meaning of dimensionless parameter , which is to be significantly greater. It is proposed to perform the processing of the experimental results published in 1993 by Yu.A. Kucherenko with co-authors considering stated generalities. Thus, one may damp the variance in the experimental description of the coefficient b. The authors of this paper obtained that b = 0,63 0,13.

M.D. Churazov
VANT. Ser.: Mat. Mod. Fiz. Proc. 2001. No 1. P. 20-28.

The conditions for thermonuclear targets ignition in the designed plants of heavy-ion thermonuclear fusion are studied using numerical simulations within the framework of multidimensional multitempetature hydrodynamics. A new scheme of cylindrical target is considered as an alternate variant for radiative targets of "Hohlraum" type using a heavy ion beam in the Fast-Ignition regime.
    It is found that a TD target ignition necessitates a high power supply J_m410⁶ TWt/g, which is achieved by the use of the ions with the energy e_i = 100 GeV. The total energy of the igniting beam is E_ign ~ 0,4 MJ. The propagation of a thermonuclear burning wave from an initiating area provides the thermonuclear gain G_DT 100 with the total energy E_o ~ 5 MJ of a driver for compression and ignition.
    A description is given of the new numerical MDMT method whereby the results were gained.

V.P. Romanikhin
VANT. Ser.: Mat. Mod. Fiz. Proc. 2001. No 1. P. 29-33.

A realization of a method for calculating differential sections of elastic scattering of electrons with the energy of 30 eV - 300 keV by atoms and molecules of a substance is described. A phase method was used for solving relativistic wave equations of electron motion within atom field. Test computations showed good agreement of the results with independent computed and experimental data.

V.A. Bychenkov, S.V. Dem'yanovsky, N.S. Zhilyaeva, A.V. Skovpen, L.V. Khardina
VANT. Ser.: Mat. Mod. Fiz. Proc. 2001. No 1. P. 34-47.

The paper presents the results of numerical studies of seismic source of an underground nuclear explosion affected by the environment, namely, rock massive geology, concavity or convexity availability, depth and yield of the explosion, the initial state of stress in rock (hydrostatic or tensor) etc. A study is made of the feasibility of seismic signal attenuation with a lower-yield explosion at a greater depth.

V.A. Bychenkov, S.V. Dem'yanovsky, Z.N. Shilyaeva, G.V. Kovalenko, I.I. Kuznetsova, A.V. Skovpen, L.V. Khardina, V.N. Shchukin
VANT. Ser.: Mat. Mod. Fiz. Proc. 2001. No 1. P. 48-57.

A technique is developed for modeling the seismic source of an underground nuclear explosion in a large air cavities without considering radiation transfer. The data from adiabatic calculations of decoupling of explosions in cavities filled with air or porous material in axially symmetric formulation with horizontal rock lamination are presented. The impact of the cavity shape and charge location upon decoupling has been studied.

N.I. Obodan, N.A. Guk
VANT. Ser.: Mat. Mod. Fiz. Proc. 2001. No 1. P. 58-62.

The behaviour of a thin-wall construction affected by non-stationary heating is considered. An approach similar to an averaging method is used for finding a solution. Two cases are studied to determine an amplitude and a phase of oscillations: the case of the main resonance and the non-resonance one. In the non-resonance case stationary oscillations are set up; an amplitude is defined by boundary conditions. In the case of the main resonance an eigenvalues problem is solved; the instant of time at which the process is characterized by appearance of a new solution is defined as a parameter. A numerical solution algorithm is described. The paper presents calculated data and determines the times at which a stressed and strained state initiating change of equilibrium configuration occurs.

M.P. Kuzhel
VANT. Ser.: Mat. Mod. Fiz. Proc. 2001. No 1. P. 63-66.

The paper considers one of the possible (in the author's opinion) effects on the results of bench testing of armour compositions. The tests may differ essentially according to the chosen means of modeling speed of bullet meeting with obstacles. The means of modeling may be the following: finding the required distance for firing with bullets of design cartridges by trial and error or firing obstacles at the smallest distances with bullets of the cartridges with modified powder weight. In the latter case an artificial enhancement of armour resistance of the obstacles tested may occur.