Interesting modelling of intense electron flow has been done with implicit particle-in-cell simulation codes. In this report, the direct implicit PIC simulation approach is applied to simulations that include full electromagnetic fields. The resulting algorithm offers advantages relative to moment implicit electromagnetic algorithms and may help in our quest for robust and simpler implicit codes.

As a satellite to the MARS (Mirror Advanced Reactor Study) a smaller, near-term device has been scoped, called the FPD (Fusion Power Demonstration). Envisioned as the next logical step toward a power reactor, it would advance the mirror fusion program beyond MFTF-B and provide an intermediate step toward commercial fusion power. Breakeven net electric power capability would be the goal such that no net utility power would be required to sustain the operation. A phased implementation is envisioned, with a deuterium checkout first to verify the plasma systems before significant neutron activation has occurred. Major tritium-related facilities would be installed with the second phase to produce sufficient fusion power to supply the recirculating power to maintain the neutral beams, ECRH, magnets and other auxiliary equipment.

The shorted stub filter (SSF) has been used extensively to provide the electronics gain shaping for stochastic cooling of longitudinal beam emittance. The repetitive notch of this filter results from the cancellation of the incident signal by the reflected signal at frequencies where the cable electrical length equals an integer number of half wavelengths. Variations in notch depth of the SSF have been approximately compensated by a rather complicated system. Dispersion of the notch frequency resulting from variation of the phase velocity can also be approximately corrected using tuned imperfections in the shorted cable. Dispersion due to imperfections in the coaxial cable can be quite significant and can only be compensated for by costly construction techniques. This paper describes another type of notch filter. Although this filter has been mentioned previously, this analysis demonstrates the advantages of this filter in providing small notch dispersion and other properties necessary for stochastic cooling systems. Because this filter uses only forward signals, it is quite insensitive to imperfections in cables and components, and can therefore be constructed from commercially available components.

Superconducting accelerator magnets usually have magnetic iron yokes to obtain maximum magnetic field and to limit stray field. However, the iron is expensive and heavy. The smaller size and weight of an iron-free magnet can result in lower magnet and refrigeration costs. However in a colliding beam accelerator the stray field from one ring produces aberrations in the field in the other. A way to eliminate this mutual interference is to surround each magnet with a coil that exactly cancels the field from the other ring magnet. That is expensive in terms of superconductor requirements. However, the cancellation of the external dipole field component is unnecessary. Only a small amount of superconductor is required for cancellation of the higher-order field-aberration components. Parameters for the iron-free magnet concept are investigated, and a preliminary conceptual design for an accelerator is presented.

The elevation radiation patterns of a stacked array of vertical electric dipoles (VEDs) over several different azimuthally symmetric inhomogeneous ground systems are studied using an integral formulation. As the ground influences the pattern of each VED differently, there is no known optimum array excitation which can be used to achieve desired beam shaping and steering. Patterns in an array of 21 VEDs spaced 0.1 lambda apart are computed and compared to HF (10 MHz) for three excitation functions: (a) conventional linear spacial phasing, (b) phasing according to the complex conjugate of the field produced by each VED in the direction of steering, and (c) spacially sinusoidal excitation with constant phasing. Results are given for grounds consisting of homogeneous earth, a perfectly conducting ground plane, a perfectly conducting disk on homogeneous earth and 2 lambda long radial wire ground systems on well- and poorly-conducting earth. It is found that the radiation pattern cannot be steered below about 9/sup 0/ in elevation for any of the excitation functions or the ground systems used. For low-angle steering conjugate excitation produces a slightly narrower beam with smaller sidelobes. Highly conducting grounds tend to permit steering to slightly higher elevations with narrower beams.

The field of a digital-image processing has experienced dramatic growth and increasingly widespread applicability in recent years. Fortunately, advances in computer technology have kept pace with the rapid growth in volume of image data in these and other applications. Digital image processing has become economical in many fields of research and in industrial and military applications. While each application has requirements unique from the others, all are concerned with faster, cheaper, more accurate, and more extensive computation. The trend is toward real-time and interactive operations, where the user of the system obtains preliminary results within a short enough time that the next decision can be made by the human processor without loss of concentration on the task at hand. An example of this is the obtaining of two-dimensional (2-D) computer-aided tomography (CAT) images. A medical decision might be made while the patient is still under observation rather than days later.

The Wire Transport Code was developed to study the dynamics of relativistic-electron-beam propagation in the transport tube in which a wire-conditioning zone is present. In order for the beam to propagate successfully in the transport section it must be matched onto the wire by focusing elements. The beam must then be controlled by strong lenses as it exits the wire zone. The wire transport code was developed to model this process in substantial detail. It is able to treat axially symmetric problems as well as those in which the beam is transversely displaced from the axis of the transport tube. The focusing effects of foils and various beamline lenses are included in the calculations.

The Mirror Advanced Reactor Study (MARS) is a conceptual design study for a commercial fusion power reactor. One of the major goals of MARS is to develop design guidance so that fusion reactors can meet reasonable expectations for environmental health and safety. One of the first steps in the assessment of health and safety requirements was to examine what the guidelines might be for health and safety in disposal of radioactive wastes from fusion reactors. Then, using these quidelines as criteria, the impact of materials selection upon generation of radioactive wastes through neutron activation of structural materials was investigated. A conclusion of this work is that fusion power systems may need substantial engineering effort in new materials development and selection to meet the probable publicly acceptable levels of radioactivity for waste disposal in the future.

The mechanical design and construction of a 199.3 MHz heavy ion RFQ for charge states q/A as low as 0.14 is described. The vane supports and positioning adjustments are significant features of this design. They provide the capability of achieving the precision vane alignment required. The maximum difference between calculated and measured apertures between the vanes is 0.0035 inches, and the average difference is 0.0010 inches. Various important aspects of the design and construction including material selection and plating, RF joints, thermal loading and vacuum system are described. Assembly techniques, methods of mechanical measurement, alignment and structure stability are discussed in detail.

This paper is organized in the following manner. In the second section we discussed absorption; the dependence of scattered light signatures of parametric instabilities occurring at n/sub e/ less than or equal to n/sub c//4 on corona size is shown in section three; and evidence for suprathermal electron production in these long-scale length plasmas is presented in section four. The results and conclusions are finally summarized in section five.

A new integrated power and breeding blanket is described. The blanket incorporates features that make it suitable for synthetic fuel production. It is matched to the thermal and electrical requirements of the General atomic water-splitting process for producing hydrogen. The fusion reaction is the Tandem Mirror Reactor (TMR) using Mirror Advanced Reactor Study (MARS) physics. The canister blanket is a high temperature, pressure balanced, cross-flow heat exchanger contained within a low activity, independently cooled, moderate temperature, first wall structural envelope. The canister uses Li/sub 2/O as the moderator/breeder and helium as the coolant. In situ tritium control, combined with slip stream processing and self-healing permeation barriers, assures a hydrogen product essentially free of tritium. The blanket is particularly adapted to synfuels production but is equally useful for electricity production or co-generation.

The two-year Mirror Advanced Reactor Study (MARS) has resulted in the conceptual design of a commercial, electricity-producing fusion reactor based on tandem mirror confinement. The physics basis for the MARS reactor was developed through work in two highly coupled areas of plasma engineering: magnetics and plasma performance.

Since the introduction of the 168//sub E/, emulating processors have been successful over an amazingly wide range of applications. This paper will describe a second generation processor, the 3081//sub E/. This new processor, which is being developed as a collaboration between SLAC and CERN, goes beyond just fixing the obvious faults of the 168//sub E/. Not only will the 3081//sub E/ have much more memory space, incorporate many more IBM instructions, and have much more memory space, incorporate many more IBM instructions, and have full double precision floating point arithmetic, but it will also have faster execution times and be much simpler to build, debug, and maintain. The simple interface and reasonable cost of the 168//sub E/ will be maintained for the 3081//sub E/.

A lithium-lens focusing device will be used for the collection of 8-GeV antiprotons in the Fermilab Tevatron I Project. The details of the mechanical and electrical design of the Fermilab lens and its associated toroidal transformer are discussed. The lens, with a radium of 1 cm and length 15 cm, is expected to achieve gradients of 1000 T/m for a focal distance of 0.225 m. The gradient requires a current on the order of 5 x 10/sup 5/A, resulting in large electromagnetic and thermal stresses. The power-supply discharge current and the effect of the inductance of the power leads and connections are minimized by the use of a toroidal matching transformer surrounding the lens itself.

In discussing upper-main-sequence stars and their intrinsic pulsations, we need to realize that theory has not yet been able to understand these pulsations. In many discussions the character of the pulsations has been described, and in many cases these theoretical solutions of the stellar pulsation theory may be the actual ones occurring. But the specific driving mechanism, so well known for the yellow and red giants and supergiants, and very recently known for the white dwarf stars, remains the subject for intense discussion. My ideas will pervade all my discussion, but many of them concerning the details such as the cause of the pulsations have not yet been proved correct.

A Cs ion-beam-transport experiment is in progress to study beam behavior under extreme space-charge conditions. A five-lens section matches the beam into a periodic electrostatic quadrupole FODO channel and its behavior is found to agree with predictions. With the available parameters (less than or equal to 200 keV, less than or equal to 20 mA, ..pi..epsilon/sub n/ greater than or equal to 10/sup -7/ ..pi.. rad-m, up to 41 periods) the transverse (betatron) occillation frequency (nu) can be depressed down to one-tenth of its zero current value (nu/sub 0/), where nu/sup 2/ = nu/sub 0//sup 2/ -..omega../sub p//sup 2//2, and ..omega../sub p/ is the beam plasma frequency. The current can be controlled by adjustment of the gun and the emittance can be controlled independently by means of a set of charged grids.

In linear accelerators the maximum achievable beam current is often limited by the Beam Breakup (BBU) instability. This instability arises from the interaction of a transversely displaced beam with the dipole modes of the acceleration cavities. The modes of interest have non-zero transverse magnetic fields at the center of the cavity. This oscillating field imparts a time varying transverse impulse to the beam as it passes through the accelerating gap. Of the various modes possible only the TM/sub 130/ mode has been observed on the Experimental Test Accelerator (ETA) and it is expected to surface on the Advanced Test Accelerator (ATA). The amplitude of the instability depends sensitively on two cavity parameters; Q and Z/sub perpendicular//Q. Q is the well-known qualtiy factor which characterizes the damping rate of an oscillator. Z/sub perpendicular//Q is a measure of how well the beam couples to the cavity fields of the mode and in turn, how the fields act back on the beam. Lowering the values of both these parameters reduces BBU growth.

We turn to the effects on opacities of atomic lines and molecular bands. It was the realization that these atomic lines were important for the opacity and the radiation flow in stars that allowed the field of stellar evolution to greatly flower in the 1960's and 1970's. Our understanding of stellar structure and evolution is now very deep.

The operation of a solid state drift chamber is described, and its use in a high rate, high multiplicity environment is discussed. The Solid State Drift Chamber (SSDCH) is a thin wafer of a high purity n-type silicon (few cm/sup 2/ x a few hundreds ..mu..m thick) with a single small-area, small-capacitance anode readout. The drift voltage is supplied to an array of drift electrodes on both sides of the wafer to produce a uniform drift field parallel to the surface of the wafer and to ensure the complete depletion of the wafer. (WHK)

We have developed a dump for the ATA beam that consists of a series of carbon plates whose collective thickness totals approximately 1.5 ranges at 50 MeV. The energy dissipated in the plates is radiated to a water-cooled wall. The dump is designed to dissipate up to 175 kW of average power. A small hole along the axis of the plates forms a beamlet that passes through an energy analyzer. The analyzer consists of a 60/sup 0/ bending magnet and two high-sensitivity beam-current/position monitors. The ratio of the beamlet current to full current is used to estimate the beam emittance.

Experiments in which the powers of two SLAC klystrons were combined and fed into a resonant cavity pulse-compression system (SLED) are described. Pulse powers up to 65 MW into SLED were reached. The corresponding instantaneous peak power out of SLED was 390 MW. After normal initial aging, no persistent RF breakdown problems were encountered. X-radiation at the SLED cavities was generally less than 400 mR/h after aging. The theoretical relationship between x-radiation intensity and RF electric field strength is discussed.

The LBL Magnetic Measurements Engineering (MME) Group has developed a Real-Time Data Acquisition System (DAS) for magnetic measurements. The design objective was for a system that was versatile, portable, modular, expandable, quickly and easily reconfigurable both in hardware and software, and inexpensive. All objectives except the last were attained. An LSI 11/23 microcomputer is interfaced to a clock-calendar, printer, CRT control terminal, plotter with hard copy, floppy and hard disks, GPIB, and CAMAC buses. Off-the-shelf hardware and software have been used where possible. Operational capabilities include: (1) measurement of high permeability materials; (2) harmonic error analysis of (a) superconducting dipoles and (b) rare earth cobalt (REC) and conventional quadrupole magnets; and (3) 0.1% accuracy x-y mapping with Hall probes. Results are typically presented in both tabular and graphical form during measurements. Only minutes are required to switch from one measurement capability to another. Brief descriptions of the DAS capabilities, some of the special instrumentation developed to implement these capabilities, and planned developments are given below.

800 MHz lower hybrid waves have been launched into PLT with a six waveguide coupler. Recent improvements have allowed powers up to 400 kW to be launched with good coupling (R approx. 10 to 25%). Experiments at low density (anti n/sub e/ < 7 x 10/sup 12/ cm/sup -3/, i.e., ..omega../..omega../sub LH/ > 2) have demonstrated current drive and plasma heating. Experiments at higher densities have produced hot-ion tails, but so far have shown inefficient body heating. To date, only a limited parameters space has been investigated at high power.

Call constants and volume per formula weight are tabulated for RE NiSn (RE = La to Lu, Y) and RE PdSn (RE = Nd to Ho). The unit cell constants are also plotted versus ionic radius of the RE; trends are noted. (DLC)