The experimental results of Faraday rotation (FR) measurements in dilute magnetic semiconductors in high magnetic field (`Dirac Series' – Los Alamos) are presented. The magnetic field is produced by an explosive-driven flux-compression generator (150T). Measurements have been carried with samples of Cd1−xMnxTe with x=0.43 using 633nm light at liquid helium temperature. The FR increases in such samples when the magnetic field exceeds 60T. Interband exchange interaction and the direct influence of the external magnetic field on the exchange interaction must be considered to interpret the experimental results.

Summary form only given. We are developing an explosive pulsed power system for the purpose of driving cylindrical solid liner implosions. A Ranchero module is a simultaneously initiated coaxial magnetic flux compression generator with an OD of 30 centimeters and an initial inductance of /spl sim/195 nH. Ultimately, we expect to perform experiments at current levels of 70-90 MA, but our near term goal is to conduct experiments in the range of 25 to 50 MA for the purpose of powering implosions of interest to the Atlas program. Development of the full-length module is progressing, and experiments to date have utilized a one-third length explosive system. We have performed experiments with: i) 1.8 MA initial current and 45 MA final current into a 1 nH static load; and 2) 4.6 MA initial current and 40 MA final current into a 5 nH static load. These experiments are described, along with expectations for liner experiments that can be conducted in anticipation of the needs of the Atlas machine when it is commissioned.

The experimental results of Faraday rotation (FR) measurements in the sample with Eu3+ ion at 4K in high magnetic fields up to 700T (`Dirac Series' – Los Alamos) are presented. The magnetic field is produced by the explosive-driven flux-compression generator MC-1. Measurements have been carried using 850nm light at liquid helium temperature. The magnetic field-induced quantum reorientation of the spin and orbital magnetic moments in the Sm3+ and Eu3+ ions have been investigated.

The Hydrodynamic and X-ray Physics Group (P-22) at Los Alamos National Laboratory has developed hardware, software, and procedures to work with explosively driven high current generators to obtain time resolved data. Data recording in this physically and electrically harsh environment requires special equipment, techniques, and processes. To avoid ground loops and EMI noise problems, fiber optic techniques are used to deliver the data from the shot pad to the recording area in the bunker. Data from electrical B-dot, V-dot, Rogowski, X-ray diodes, Faraday rotation current measurements, are all part of the diagnostic probes that are routinely recorded by our data acquisition systems. Shielded 50 Ohms coaxial cables deliver the electrical probe signals to an area close to the device, generally about 50 feet, behind a blast shield. Behind the blast shield are several EMI shielded boxes containing fiber optic transmitters and proper attenuation for the probe signals. These fiber optic transmitters are battery powered and are allowed to float electrically. The bunker area contains the fiber optic receivers, waveform digitizers, triggering equipment and data acquisition computers. From the shot pad area optical fibers provide the signal path into the bunker and the fiber optic receivers. Where necessary the bunker ground loops are broken with fiber optic trigger hardware and large-scale uninterruptable power supplies (UPS). These units have storage batteries to provide clean AC power to operate the data recording equipment during the experiment.

We are developing a high explosive pulsed power system concept that we call Ranchero. Ranchero systems consist of series-parallel combinations of simultaneously initiated coaxial magnetic flux compression generators, and are intended to operate in the range from 50 MA to a few hundred MA currents. One example of a Ranchero system is shown. The coaxial modules lend themselves to extracting the current output either from one end or along the generator midplane. In this paper we concentrate on the system that we will use for our first imploding liner tests, a single module with end output. The module is 1.4 m long and expands the armature by a factor of two to reach the 30 cm OD stator. Our first heavy liner implosion experiments will be conducted in the range of 40-50 MA currents. Electrical tests, to date, have employed high explosive (HE) charges 43 cm long. We have performed tests and related 1D MHD calculations at the 45-MA current level with small loads. From these results, we determine that we can deliver currents of approximately 50 MA to loads of 8 nH.

High explosive pulsed power (HEPP) systems are capable of generating very high energies in magnetic fields. Such stored energy is usually developed on time scales of a few tens or hundreds of microseconds. Many applications require shorter pulses and opening switches provide one way to use the large energy available for faster applications. With current flowing in an inductive circuit, introducing resistance produces voltage that can be used to drive current into a load. For an opening switch with a fast rising resistance, the load current rise time is determined by the R/L time constant of the circuit. A significant fraction of the circuit energy must be dissipated in the process, and in applications where very large energies must be dealt with only a few types of switches can be used. Experiments with high explosive driven opening switches have produced a few switches that can carry tens of MA current, and open on the time scale of one or a few /spl mu/s. We have specialized in a type of switch that we call an explosively formed fuse (EFF), and the use of this switch in the is MJ Procyon system is the subject of this paper. Operation of the EFF switch at levels of /spl sim/3 TW for 2 /spl mu/s has become routine, and we describe its characteristics and give data from a number of tests.

The Procyon explosive pulsed power system is designed for powering plasma z-pinch experiments. It begins with a helical explosive-driven magnetic flux compression generator (MCG) for amplifying seed current from a capacitor bank into a storage inductor. One conductor element of the storage inductor is an explosively formed fuse (EFF) opening switch tailored to divert current to a plasma flow switch (PFS) in less than 3 [mu]s. The PFS, in turn, delivers current to a z-pinch load. Experiments to date have concentrated on the explosive pulsed power components and PFS. This paper focuses on the results of a recent full energy MCG/EFF/PFS test.

We describe an optical system which produces two simultaneous, time-gated, magnified images of the back-side of a planar laser target. The two views of the target are from different directions relative to the target normal but may be chosen to be at the same angle relative to the direction of incidence of the laser beam so as to permit cancellation of any angular correlation relative to the laser beam direction. The two images are amplified by a time-gated channel-plate intensifier (CPI) and recorded on 35 mm film. This device permits measurement of the angular distribution relative to the target normal of light emitted from the back-side of laser targets as a function of time relative to the start of the laser pulse; such measurements are required in an experiment described in the report, "The Limb-Darkening Opacity Experiment Using a Laser-Heated Plasma," LA-7484-MS. We describe the operation of the device and discuss an important instrumental effect due to non-simultaneous gating of different portions of the CPI tube whereby an incorrrect angular distribution can be obtained. We discuss precautions necessary to insure that this does not occur. Samples of data will be presented.