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EBQ code: transport of space-charge beams in axially symmetric devices

Description: Such general-purpose space charge codes as EGUN, BATES, WOLF, and TRANSPORT do not gracefully accommodate the simulation of relativistic space-charged beams propagating a long distance in axially symmetric devices where a high degree of cancellation has occurred between the self-magnetic and self-electric forces of the beam. The EBQ code was written specifically to follow high current beam particles where space charge is important in long distance flight in axially symmetric machines possessing external electric and magnetic field. EBQ simultaneously tracks all trajectories so as to allow procedures for charge deposition based on inter-ray separations. The orbits are treated in Cartesian geometry (position and momentum) with z as the independent variable. Poisson's equation is solved in cylindrical geometry on an orthogonal rectangular mesh. EBQ can also handle problems involving multiple ion species where the space charge from each must be included. Such problems arise in the design of ion sources where different charge and mass states are present.
Date: November 1, 1982
Creator: Paul, A.C.
Partner: UNT Libraries Government Documents Department

CBEAM. 2-D: a two-dimensional beam field code

Description: CBEAM.2-D is a two-dimensional solution of Maxwell's equations for the case of an electron beam propagating through an air medium. Solutions are performed in the beam-retarded time frame. Conductivity is calculated self-consistently with field equations, allowing sophisticated dependence of plasma parameters to be handled. A unique feature of the code is that it is implemented on an IBM PC microcomputer in the BASIC language. Consequently, it should be available to a wide audience.
Date: May 1, 1985
Creator: Dreyer, K.A.
Partner: UNT Libraries Government Documents Department

Blanket technology experiments at Argonne National Laboratory

Description: Argonne National Laboratory has the largest US program for the development of blanket technology. The goals of the program are to resolve critical issues for different blanket concepts, to develop the understanding and predictive capability of blanket behavior, and to develop the technology needed to build and operate advanced fusion blankets. The projects within the program are liquid metal MHD, breeder neutronics, tritium oxidation, transient electromagnetics, FLIBE chemistry, and insulator coatings. The present status and recent results of the projects are described.
Date: February 1, 1988
Creator: Mattas, R.F.; Reed, C.B.; Picologlou, B.; Finn, P.; Clemmer, R.; Porges, K. et al.
Partner: UNT Libraries Government Documents Department

Nonperturbative analysis of the two-level atom: Applications to multiphoton excitation

Description: Selective excitation in an atomic system subjected to a slowly varying external electromagnetic field is studied using a two-level model. Time evolution of the system is found using an approach which is nonperturbative in the field strength. There is no constraint to small values of the applied field, that is, the field (in appropriate energy units) need not be small compared to the difference in energies of the two levels. Rather, we prey upon the fact that the situation of interest to us is where the frequency of the exciting field is small compared to the frequency associated with the level difference. Transition probabilities and resonance conditions are found which circumscribe both the large and small field limits. In the weak field limit the previous results of high-order perturbation theory are readily recovered. For a monochromatic field the characteristic features of resonance excitation at high harmonic number of the applied field are (a) extremely narrow resonance widths and (b) shifts in resonance positions which are strong functions of field intensity. Because of this sensitivity, we are able to demonstrate that when slow temporal evolution of the field amplitude is taken into account (e.g., due to finite pulse duration) the appropriate mean excitation rate is that due to the uncorrelated contribution of many resonances. The results of this analysis are used to estimate excitation rates in a specific atomic system, Cd/sup 12 +/, which are then compared to multiphoton ionization rates. Our calculations suggest that the ionization rate exceeds the excitation rate by several orders of magnitude. 15 refs., 3 figs.
Date: August 1, 1987
Creator: Duvall, R.E.; Valeo, E.J. & Oberman, C.R.
Partner: UNT Libraries Government Documents Department

Linear optimal control of tokamak fusion devices

Description: The control of plasma position, shape and current in a tokamak fusion reactor is examined using linear optimal control. These advanced tokamaks are characterized by non up-down symmetric coils and structure, thick structure surrounding the plasma, eddy currents, shaped plasmas, superconducting coils, vertically unstable plasmas, and hybrid function coils providing ohmic heating, vertical field, radial field, and shaping field. Models of the electromagnetic environment in a tokamak are derived and used to construct control gains that are tested in nonlinear simulations with initial perturbations. The issues of applying linear optimal control to advanced tokamaks are addressed, including complex equilibrium control, choice of cost functional weights, the coil voltage limit, discrete control, and order reduction. Results indicate that the linear optimal control is a feasible technique for controlling advanced tokamaks where the more common classical control will be severely strained or will not work. 28 refs., 13 figs.
Date: May 1, 1989
Creator: Kessel, C.E.; Firestone, M.A. & Conn, R.W.
Partner: UNT Libraries Government Documents Department

Beamline considerations for a compact, high current, high power linear RF electron accelerator

Description: A design for a compact, high current, high power linear electron accelerator using an rf power source is investigated. It consists of adjacent cavities into which rf power is injected and through which electron pulses pass. The source is assumed to be capable of delivering sufficient rf power to the desired location at the proper phase. Beamline issues such as cavity loading, energy extraction, longitudinal and transverse pulse focusing, and beam breakup are considered. A device which, given the required source, can deliver beam parameters comparable to existing induction accelerators but which is more than an order of magnitude smaller appears feasible.
Date: June 1, 1987
Creator: Marder, B.
Partner: UNT Libraries Government Documents Department

Introduction to wakefields and wake potentials

Description: What are wakefields and wake potentials, and why are these concepts useful in the physics of linear accelerators and storage rings We approach this question by first reviewing the basic physical concepts which underlie the mathematical formalism. We then present a summary of the various techniques that have been developed to make detailed calculations of wake potentials. Finally, we give some applications to current problems of interest in accelerator physics. No attempt at completeness can be made in an introductory article of modest length. Rather, we try to give a broad overview and to list key references for more detailed study. It will also be apparent that the last chapter on this subject, with all the loose ends neatly tied up, has yet to be written. There are subtle points, there are controversial questions, and active calculations to resolve these questions are continuing at the time of this writing. 61 refs., 10 figs., 1 tab.
Date: January 1, 1989
Creator: Wilson, P.B.
Partner: UNT Libraries Government Documents Department

Wake field accelerators

Description: In a wake field accelerator a high current driving bunch injected into a structure or plasma produces intense induced fields, which are in turn used to accelerate a trailing charge or bunch. The basic concepts of wake field acceleration are described. Wake potentials for closed cavities and periodic structures are derived, as are wake potentials on a collinear path with a charge distribution. Cylindrically symmetric structures excited by a beam in the form of a ring are considered. (LEW)
Date: February 1, 1986
Creator: Wilson, P.B.
Partner: UNT Libraries Government Documents Department

Measurements of the electrostatic and electromagnetic fields of Faraday shielding half-turn loop type ICRF antennae

Description: Detailed measurements of both the electrostatic and electromagnetic fields are performed for various types of Faraday shields mounted on PLT ICRF antennae. The data show that the shields have little effect on the electromagnetic fields when the antenna is driven such that it is generating a constant total flux for the various cases. A new type of shield (Type II) is investigated that has no effect on the antenna inductance and performs equally as well as the conventional shields (Type I) in shielding out the electrostatic fields. Measurements indicate, for the shields investigated, that each layer of shield strips degrade the Q by approximately a factor of two.
Date: December 1, 1984
Creator: Fortgang, C.M. & Hwang, D.Q.
Partner: UNT Libraries Government Documents Department

Different ways of looking at the electromagnetic vacuum

Description: Some thoughts on the electromagnetic vacuum are presented in connection with the vacuum and source fields as alternative physical bases for understanding spontaneous emission, the Lamb shift, Casimir effects, van der Waals forces, and the ''thermalization'' of vacuum fluctuations for a uniformly accelerated observer.
Date: January 1, 1987
Creator: Milonni, P.W.
Partner: UNT Libraries Government Documents Department

Choice of parameters for linear colliders in multi-bunch mode

Description: The energy efficiency of a linear collider in multi-bunch mode is calculated for the case that the bunches in each of the two interacting beams are identical in all interaction points, a configuration which can be realized by taking advantage of the beam-beam effect between beams of opposite electric charge. The maximization of the efficiency is discussed, the maximum appears to increase nearly linearly with beam brightness and accelerating gradient, and about quadratically with the length of the ir. The optimum operating frequency for the linacs increases also, while the pulse repetition rate and the beam current needed for fixed luminosity, decrease. The increasing brightness and the decreasing current needed for higher efficiency lead to smaller transverse spotsizes in the crossing points; this imposes tighter tolerances on the relative transverse coordinates of the two beam-axes. Pillbox or similar resonators, excited in the TM01 mode, may be preferable to quadrupoles for transverse focusing, at the high frequencies and gradients that seem desirable, particularly in the final focus. 4 refs., 7 figs.
Date: January 1, 1987
Creator: Claus, J.
Partner: UNT Libraries Government Documents Department

Geometrical properties of an internal local octonionic space in curved space time

Description: A geometrical treatment on a flat tangent space local to a generalized complex, quaternionic, and octonionic space-time is constructed. It is shown that it is possible to find an Einstein-Maxwell-Yang-Mills correspondence in this generalized (Minkowskian) tangent space. 9 refs.
Date: April 1, 1986
Creator: Marques, S. & Oliveira, C.G.
Partner: UNT Libraries Government Documents Department

An investigation of the usefulness of extremely low-frequency electromagnetic measurements for treaty verification

Description: From FY 1986 through FY 1988, we monitored extremely low-frequency (ELF) electromagnetic (EM) fields to determine whether these signals could be detected from underground nuclear explosions. Signals clearly related to underground tests were detected only when the ELF field sensors were located within 10 km of surface ground zero. Theoretical analysis, based on the results of these measurements, shows that the ELF impulse signals from underground nuclear tests are of longer duration than those from lightning sources and are, therefore, less efficient in exciting resonances in the earth-ionosphere cavity, even though the source strength for each may be the same. Thus, ELF signals from underground nuclear tests with yields of <150 kT are generally lower than the background signals caused by worldwide lightning activity. Our conclusion is that ELF monitoring probably will not be useful for detecting underground nuclear tests at distances >10 km from the tests. 16 refs., 24 figs., 3 tabs.
Date: January 1, 1989
Creator: Sweeney, J.J.
Partner: UNT Libraries Government Documents Department

Theory of atoms in strong, pulsed electromagnetic fields: 2, A free electron and a harmonically bound electron

Description: Multiple scale methods are used to treat several ingredients of the theory of atoms in strong electromagnetic fields. First, a focused electromagnetic field is expanded. Second, a classical electron is described giving the ponderomotive potential. Third, the quantum electron is treated in the WKB approximation. Fourth, the one dimensional quantum harmonic oscillator is solved; and last the one dimensional square well, showing the low intensity limit of the theory.
Date: July 1, 1987
Creator: Szoeke, A. & Garrison, J.
Partner: UNT Libraries Government Documents Department

Pacific Northwest Laboratory annual report for 1979 to the DOE Assistant Secretary for Environment. Part 2. Ecological sciences

Description: Research in Environment, Health, and Safety conducted during fiscal year 1979 is reported. This volume consists of project reports from the Ecological Sciences research department. The reports are grouped under the following subject areas: National Environmental Research Park and land use; Alaskan resource research; shale oil; synfuels; nuclear waste; fission; marine research programs; statistical development of field research; nuclear fusion; pumped storage and hydroelectric development; pathways modelling, assessment and Hanford project support; electric field and microwave research; and energy research for other agencies. (ACR)
Date: February 1, 1980
Creator: Vaughan, B.E.
Partner: UNT Libraries Government Documents Department

Preliminary assessment of the electromagnetic environment in the immediate vicinity of the ETA accelerator

Description: The electromagnetic fields in the immediate vicinity of the Experimental Test Accelerator (ETA) at the Lawrence Livermore Laboratory have been characterized. Various EM sensors that cover the frequency band from the very low frequencies up into the GHz region have been used. The report describes in detail the probes, the test set-up and the data processing techniques.
Date: April 1, 1980
Creator: Cabayan, H.S.; Bogdan, E.; Zicker, J.; Wythe, D. & Burke, G.J.
Partner: UNT Libraries Government Documents Department

A ring model of the lasertron

Description: A large-signal, 2-1/2 dimensional relativistic particle dynamics code has been written to simulate the electrical behavior of the lasertron. The theory and the approximations involved in this code are discussed in detail. Numerical results are presented to show the comparison with previous work and to show the general variation in lasertron performance with frequency, beam voltage, and beam current. The code has also been used to design a prototype 6-GHz lasertron for construction at the Laboratoire de l'Accelerateur Lineaire in Orsay, France. The calculations show that this prototype can produce 4.7-MW peak-power output with a conversion efficiency of 65%. At 3 GHz, the power would be increased by a factor approaching 10, and the conversion efficiency would be over 70%.
Date: January 1, 1988
Creator: Tallerico, P.J. & Coulon, J.P.
Partner: UNT Libraries Government Documents Department

Probing the vacuum with highly charged ions

Description: The physics of the Fermion vacuum is briefly described, and applied to pair production in heavy ion collisions. We consider in turn low energies (<50 MeV/nucleon), intermediate energies (<5 GeV/nucleon), and ultrahigh energies such as would be produced in a ring collider. At high energies, interesting questions of Lorentz and gauge invariance arise. Finally, some applications to the structure of high Z atoms are examined. 14 refs., 11 figs.
Date: January 1, 1987
Creator: Bottcher, C. & Strayer, M.R.
Partner: UNT Libraries Government Documents Department

Investigation of electromagnetic launcher behavior for impact fusion. Annual report, May 1, 1984-April 30, 1985

Description: The second year of a 4-year program to develop an ultra-high velocity electromagnetic launcher has been completed, with significant progress made in the key technical areas. This lays firmly the cornerstone for major progress in Year 3 of the program. The launcher instrumentation and diagnostics system was developed. More than 20 launcher experiments were conducted using the SUVAC-I augmented launcher system. We tested our novel plasma generation technique using a lithium seeded propellant with encouraging success. We accelerated a 1.4 g projectile to 5.3 km/s in 1.6 m in the series. Unaugmented barrels for SUVAC-II were fabricated. The barrels were tested and commissioned with a total of 8 firings in single-stage configurations. The tests verified the basic soundness of the barrel mechanical and electrical design. Velocity up to 4.4 km/s was achieved with a 1.1 g projectile. Concurrently, we completed the fabrication, assembly and installation of SUVAC-II power supply (1 MJ) and its expanded control system. Experimentation with the multi-stage SUVAC-II launcher is expected to take place in the early part of Year 3. In the meantime, fabrication of the SUVAC-III power supply (an additional 0.4 MJ) has also been initiated.
Date: May 1, 1985
Creator: Thio, Y.C.
Partner: UNT Libraries Government Documents Department

Experimental observations of the coupling between induced currents and mechanical motion in torsionally supported square loops and plates. Part 1. Experimental analysis

Description: This two-part report describes a series of experiments designed to provide quantitative data on coupled magnetomechanical systems. This first part presents the details of the data analysis, some representative data, the overall results, and conclusions. The Fusion Electromagnetic Induction Experiment (FELIX) facility is described at the Argonne National Laboratory (ANL), where the experiments were performed, and the test fixture which was designed for this investigation. The next section describes the static and dynamic mechanical tests which were performed with the test fixture and summarizes the results. The sixth section presents and summarizes the results of the tests which were made with the dipole field only, which produces no mechanical rotation. The total electric current flowing around a test piece was measured versus time using a Rogowski coil. The seventh section presents and summarizes the results of actual coupled tests which were made with both the dipole field and solenoid field. Both the test piece Rogowski coil and the rotational transducer were employed for these tests.
Date: November 1, 1984
Creator: Weissenburger, D.W.; Bialek, J.M.; Cargulia, G.J.; Ulrickson, M.; Knott, M.J.; Turner, L.R. et al.
Partner: UNT Libraries Government Documents Department

Experimental observations of the coupling between induced currents and mechanical motion in torsionally supported square loops and plates. Part 2. Data inventory

Description: A series of experiments was successfully conducted to investigate the coupling between induced currents and rigid body rotation in square loops and plates. The experiments were performed with the Fusion Electromagnetic Induction Experiment (FELIX) facility at the Argonne National Laboratory. The observed data exhibited the magnetic damping and magnetic stiffness effects ehich arise in coupled systems and agreed very well with previous analytic calculations.
Date: December 1, 1984
Creator: Weissenburger, D.W.; Bialek, J.M.; Cargulia, G.J.; Ulrickson, M.; Knott, M.J.; Turner, L.R. et al.
Partner: UNT Libraries Government Documents Department

Translation operator for finite dmensional electromagnetic fields

Description: Computation of electromagnetic fields in particular applications is usually accompanied by the adhoc assumption that the field contains a finite number of degrees of freedom. Herein, this assumption is made at the outset. It is shown that if an annular region between two closed surfaces contains no sources or sinks and is isotropic, lossless and homogeneous, a unique translation operator can be defined algebraically. Conservation of energy defines the translation operator T to within an arbitrary unitary transformation. The conditions of causality, unitarity and energy conservation are shown to uniquely determine T. Both scalar and vector fields are treated. In both of these cases, frequency and time domain transforms are computed. The transform T is compared with the analagous one as derived from the time domain Stratton-Chu Formulation. The application to a radiation condition boundary constraint on finite difference and finite element computations is discussed.
Date: April 1, 1981
Creator: Howard, A.Q. Jr.
Partner: UNT Libraries Government Documents Department

The design of a large aperture high field dipole

Description: The impetus for this design report originated in the Snowmass 88 meeting where the subject of higher energies within the constraints of the existing Tevatron tunnel enclosure was investigated. It was determined that beam transport to the fixed target experimental areas was possible up to an energy of {approximately}1.5 Tev. Collider operation was feasible at somewhat higher energies (1.8 Tev), primarily limited by the ability to design a single turn beam abort system within the constraints of the straight section length. A new accelerator in the existing tunnel would, of necessity, have a similar though not identical lattice and straight section layout to the present Tevatron. Thus when issues arose in the magnet design requiring input from the accelerator standpoint we have assumed a Tevatron like machine. The possibility of using these high field magnets as elements in the existing Tevatron to create new warm space,' for another Interaction Region for example, also emphasizes compatibility with the present machine. 16 refs., 62 figs., 23 tabs.
Date: December 1, 1989
Creator: Harfoush, F.; Harrison, M.; Kerby, J.; Koepke, K.; Mantsch, P.; Nicol, T. et al.
Partner: UNT Libraries Government Documents Department