MULTI-IFE—A one-dimensional computer code for Inertial Fusion Energy (IFE) target simulations

Abstract

The code MULTI-IFE is a numerical tool devoted to the study of Inertial Fusion Energy (IFE) microcapsules. It includes the relevant physics for the implosion and thermonuclear ignition and burning: hydrodynamics of two component plasmas (ions and electrons), three-dimensional laser light ray-tracing, thermal diffusion, multigroup radiation transport, deuterium–tritium burning, and alpha particle diffusion. The corresponding differential equations are discretized in spherical one-dimensional Lagrangian coordinates. Two typical application examples, a high gain laser driven capsule and a low gain radiation driven marginally igniting capsule are discussed. In addition to phenomena relevant for IFE, the code includes also components (planar and cylindrical geometries, transport coefficients at low temperature, explicit treatment of Maxwell’s equations) that extend its range of applicability to laser–matter interaction at moderate intensities (<1016 W cm−2). The source code design has been kept simple and structured with the aim to encourage user’s modifications for specialized purposes. Program summaryProgram title: MULTI-IFECatalogue identifier: AEZR_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEZR_v1_0.htmlProgram obtainable from: CPC Program Library, Queen’s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 267428No. of bytes in distributed program, including test data, etc.: 3798542Distribution format: tar.gzProgramming language: Fortran 95.Computer: Any.Operating system: Any.RAM: 1.8 MBClassification: 19.7.Nature of problem: The implosion and ignition of inertial energy fusion capsules driven either directly by laser beams or indirectly by thermal radiation.Solution method: The one-dimensional equations of hydrodynamic motion, laser propagation, energy transport by thermal conduction and radiative transfer, deuterium–tritium thermonuclear burning, and α-particle diffusion are discretized on a Lagrangian grid, and advanced in time by a fractional step scheme. An implicit conservative method is used to treat hydrodynamics. Thermal and electrical conductivities as well as coefficients for laser absorption and electron–ion energy exchange are obtained from a two temperature (for electrons and ions) model. Laser propagation is treated by 3D tracing of the laser rays in the geometrical optics approximation. Radiation transfer is solved by using the forward–reverse method for a discrete number of frequency groups. Matter properties are interpolated from tables (equations-of-state, ionization, and opacities) generated by external codes.Restrictions: The code has been designed for typical conditions prevailing in inertial confinement fusion (ps–ns time scale, matter states close to local thermodynamic equilibrium, and negligible radiation pressure). A wider range of situations can be treated, as long as the above conditions are fulfilled. This includes, in particular, laser plasma experiments at moderate intensities (≤1016W cm−2).Unusual features: An optional graphical post-processing package is included in the distribution. This option requires a Linux/Unix operating system with the essential developing tools (C compiler; X11 libraries and include files; and the xterm command). Most of the figures in this paper have been created using this software.Additional comments: The source code design has been kept simple and structured, with the aim to encourage user’s modifications for specialized purposes. A technical manual is included in the package.Running time: 13–18 s for the examples discussed in the paper.