Atlas performance and imploding liner parameter space

Ultra-high magnetic fields have many applications in the confining and controlling plasmas and in exploring electron physics as manifested in the magnetic properties of materials. Another application of high fields is the acceleration of metal conductors to velocities higher than that achievable with conventional high explosive drive or gas guns. The Atlas pulse power system is the world's first pulse power system specifically designed to implode solid and near-solid density metal liners for use in pulse power hydrodynamic experiments. This paper describes the Atlas system during the first year of its operational life at Los Alamos, (comprising 10-15 implosion experiments); describes circuit models that adequately predicted the bulk kinematic behavior of liner implosions; and shows how those (now validated) models can be used to describe the range of parameters accessible through Atlas implosions

The VNIIEF/LANL collaboration : ten years of scientific benefit to the Russian Federation and the United States

Since 1992, the All-Russian Scientific Research Institute of Experimental Physics (VNIIEF) and the Los Alamos National Laboratory (LANL), the institutes that designed the first nuclear weapons of the Soviet Union and the United States, respectively, have been working together in fundamental research related to pulsed power technology and high energy density science. Experimental and theoretical work has been performed at Sarov and Los Alamos in areas as diverse as imploding liner physics and applications, fusion plasma formation, isentropic compression of noble gases, and explosively driven high current generation technology, all traditional areas of the Megagauss series of conferences. Recent joint work has focused on the Atlas capacitor bank (23 MJ, 30 MA, 6 ps) now operational at LANL. Even before Atlas became operational, VNIIEF's DEMG capability was used to provide the US with the first available data at ATLAS! upper performance limit (31 MA, 4 ps, 12 km/s velocity for 50 g liner mass). VNIIEF has recently designed and fielded imploding liner experiments on Atlas, with the goal of studying material strength properties by observing unstable perturbation growth. This paper traces the origins of this collaboration and reviews the scientific accomplishments

Generation and compression of a target plasma for magnetized target fusion

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). Magnetized target fusion (MTF) is intermediate between the two very different approaches to fusion: inertial and magnetic confinement fusion (ICF and MCF). Results from collaboration with a Russian MTF team on their MAGO experiments suggest they have a target plasma suitable for compression to provide an MTF proof of principle. This LDRD project had tow main objectives: first, to provide a computational basis for experimental investigation of an alternative MTF plasma, and second to explore the physics and computational needs for a continuing program. Secondary objectives included analytic and computational support for MTF experiments. The first objective was fulfilled. The second main objective has several facets to be described in the body of this report. Finally, the authors have developed tools for analyzing data collected on the MAGO a nd LDRD experiments, and have tested them on limited MAGO data

The fundamental parameter space of controlled thermonuclear fusion”,

We apply a few simple first-principles equations to identify the parameter space in which controlled fusion might be possible. Fundamental physical parameters such as minimum size, energy, and power as well as cost are estimated. We explain why the fusion fuel density in inertial confinement fusion is more than 10 11 times larger than the fuel density in magnetic confinement fusion. We introduce magnetized target fusion as one possible way of accessing a density regime that is intermediate between the two extremes of inertial confinement fusion and magnetic confinement fusion and is potentially lower cost than either of these two

Ignition and burn in inertially confined magnetized fuel

At the third International Conference on Emerging Nuclear Energy Systems, we presented computational results which suggested that breakeven'' experiments in inertial confinement fusion (ICF) may be possible with existing driver technology. We recently used the ICF simulation code LASNEX to calculate the performance of an idealized magnetized fuel target. The parameter space in which magnetized fuel operates is remote from that of both conventional'' ICF and magnetic confinement fusion devices. In particular, the plasma has a very high {beta} and is wall confined, not magnetically confined. The role of the field is to reduce the electron thermal conductivity and to partially trap the DT alphas. The plasma is contained in a pusher which is imploded to compress and adiabatically heat the plasma from an initial condition of preheat and pre-magnetization to the conditions necessary for fusion ignition. The initial density must be quite low by ICF standards in order to insure that the electron thermal conductivity is suppressed and to minimize the generation of radiation from the plasma. Because the energy loss terms are effectively suppressed, the implosion may proceed at a relatively slow rate of about 1 to 3 cm/{mu}s. Also, the need for low density fuel dictates a much larger target, so that magnetized fuel can use drivers with much lower power and power density. Therefore, magnetized fuel allows the use of efficient drivers that are not suitable for laser or particle beam fusion due to insufficient focus or too long pulse length. The ignition and burn of magnetized fuel involves very different dominant physical processes than does conventional'' ICF. The fusion time scale becomes comparable to the hydrodynamic time scale, but other processes that limit the burn in unmagnetized fuel are of no consequence. The idealized low gain magnetized fuel target presented here is large and requires a very low implosion velocity. 11 refs

Computational modeling of magentically driven liner-on-plasma fusion experiments

Magnetized Target Fusion (MTF) is an approach to controlled fusion which potentially avoids the difficulties of the traditional magnetic and inertial confinement approaches. It appears possible to investigate the critical issues for MTF at low cost, relative to traditional fusion programs, utilizing pulsed power drivers much less expensive than ICF drivers, and plasma configurations much less expensive than those needed for full magnetic confinement. Computational and experimental research into MTF is proceeding at Los Alamos, VNIIEF, and other laboratories

MHD modeling of magnetized target fusion experiments.

Magnetized Target Fusion (MTF) is an alternate approach to controlled fusion in which a dense (0(1017-'8 cm-')), preheated (O(200 ev)), and magnetized (0( 100 kG)) target plasma is hydrodynamically compressed by an imploding liner. If electron thermal conduction losses are magnetically suppressed, relatively slow O(1 cm/microsecond) 'liner-on-plasma' compressions may be practical, using liners driven by inexpensive electrical pulsed power. Target plasmas need to remain relatively free of potentially cooling contaminants during formation and compression. Magnetohydrodynamic (MHD) calculations including detailed effects of radiation, heat conduction, and resistive field diffusion have been used to model separate target plasma (Russian MAGO, Field Reversed Configuration at Los Alamos National Laboratory) and liner implosion experiments (without plasma fill), such as recently performed at the Air Force Research Laboratory (Albuquerque). Using several different codes, proposed experiments in which such liners are used to compress such target plasmas are now being modeled in one and two dimensions. In this way, it is possible to begin to investigate important issues for the design of such proposed liner-on-plasma fusion experiments. The competing processes of implosion, heating, mixing, and cooling will determine the potential for such MTF experiments to achieve fusion conditions

PROGRESS TOWARD UNDERSTANDING MAGNETIZED TARGET FUSION (MTF).

Magnetized target fusion (MTF) takes advantage of (1) the reduction of the electron thermal conductivity in a plasma due to magnetization and (2) the efficient heating through bulk compression. MTF proposes to create a warm plasma with an embedded magnetic field and to compress it using an imploded liner or shell. The minimum energy required for fusion in an optimized target is directly proportional to the mass of the ignited fusion fuel. Simple theoretical arguments and parameter studies have demonstrated that MTF has the potential for significantly reducing the power and intensity of a target driver needed to achieve fusion. In order to acquire a comprehensive understanding of MTF and its potential applications it is prudent to develop more complete and reliable computational techniques. This paper briefly reviews the progress toward that goal