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Inertial Fusion Energy Studies on an Earth Simulator-Class Computer

Description: The U.S. is developing fusion energy based on inertial confinement of the burning fusion fuel, as a complement to the magnetic confinement approach. DOE's Inertial Fusion Energy (IFE) program within the Office of Fusion Energy Sciences (OFES) is coordinated with, and gains leverage from, the much larger Inertial Confinement Fusion program of the National Nuclear Security Administration (NNSA). Advanced plasma and particle beam simulations play a major role in the IFE effort, and the program is … more
Date: August 13, 2002
Creator: Friedman, A & Stephens, R
Partner: UNT Libraries Government Documents Department
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Pulsed power and electron beams in the 21st century.

Description: Pulsed power and accelerator technology for high energy density physics, radiography, and simulation has matured to the point that new facilities promise users reliability of quality data return unheard of just a short time ago. By this metric alone these machines and accelerators have graduated from being experiments in their own right, to the solid foundation of a new era of experimental science. The projected performance of a few of these new capabilities will be highlighted, along with some… more
Date: January 1, 2002
Creator: Ekdahl, C. A. (Carl A.)
Partner: UNT Libraries Government Documents Department
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Overview of Virtual National Laboratory Objectives, Plans, andProjects

Description: Significant experimental and theoretical progress has been made in the U.S. heavy ion fusion program on high-current sources, transport, and focusing. Currents over 200 mA have been transported through a matching section and 10 half-lattice periods with electric quadrupoles. An experiment shows control of high beam current with an aperture, while avoiding secondary electrons. New theory and simulations of the neutralization of intense beam space charge with plasma in various focusing chamber co… more
Date: June 1, 2002
Creator: Logan, B. G.; Celata, C. M.; Kwan, J. W.; Lee, E. P.; Leitner, M.; Seidl, P. A. et al.
Partner: UNT Libraries Government Documents Department
open access

Applications of Magnetized Plasma to Particle Acceleration

Description: Magnetized plasma can be used as an accelerating structure capable of supporting large amplitude longitudinal fields which are externally driven by a high-frequency microwave source. Such structures can be used at very high frequencies (hundreds of gigahertz), placing them in the intermediate region between conventional (metallic) accelerators, and laser-driven plasma accelerators. They review two magnetic field configurations with respect to the direction of the particle beam propagation: (1) … more
Date: December 12, 2002
Creator: Shvets, Gennady; Wurtele, Jonathan S. & Hur, Min-Sup
Partner: UNT Libraries Government Documents Department
open access

The high current experiment: First results

Description: The High Current Experiment (HCX) is being assembled at Lawrence Berkeley National Laboratory as part of the US program to explore heavy-ion beam transport at a scale representative of the low-energy end of an induction linac driver for fusion energy production. The primary mission of this experiment is to investigate aperture fill factors acceptable for the transport of space-charge dominated heavy-ion beams at high spacecharge intensity (line-charge density {approx} 0.2 {micro}C/m) over long … more
Date: May 26, 2002
Creator: Seidl, Peter A.; Baca, D.; Bieniosek, F.M.; Faltens, A.; Lund, S.M.; Molvik, A.W. et al.
Partner: UNT Libraries Government Documents Department
open access

End-to-end simulation: The front end

Description: For the intense beams in heavy ion fusion accelerators, details of the beam distribution as it emerges from the source region can determine the beam behavior well downstream. This occurs because collective space-charge modes excited as the beam is born remain undamped for many focusing periods. Traditional studies of the source region in particle beam systems have emphasized the behavior of averaged beam characteristics, such as total current, rms beam size, or emittance, rather than the detail… more
Date: May 1, 2002
Creator: Haber, I.; Bieniosek, F. M.; Celata, C. M.; Friedman, A.; Grote, D. P.; Henestroza, E. et al.
Partner: UNT Libraries Government Documents Department
open access

Optical system design for high-energy particle beam diagnostics.

Description: Radiation generated by high-energy particle beams is widely used to characterize the beam properties. While the wavelengths of radiation may vary from visible to x-rays, the physics underlying the engineering designs are similar. In this tutorial, we discuss the basic considerations for the optical system design in the context of beam instrumentation and the constraints applied by high-radiation environments. We cover commonly used optical diagnostics: fluorescence flags, visible and x-ray sync… more
Date: August 29, 2002
Creator: Yang, B. X. Y.
Partner: UNT Libraries Government Documents Department
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Interactive visualization of particle beams for accelerator design

Description: We describe a hybrid data-representation and rendering technique for visualizing large-scale particle data generated from numerical modeling of beam dynamics. The basis of the technique is mixing volume rendering and point rendering according to particle density distribution, visibility, and the user's instruction. A hierarchical representation of the data is created on a parallel computer, allowing real-time partitioning into high-density areas for volume rendering, and low-density areas for p… more
Date: January 15, 2002
Creator: Wilson, Brett; Ma, Kwan-Liu; Qiang, Ji & Ryne, Robert
Partner: UNT Libraries Government Documents Department
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Developing high brightness and high current beams for HIF injectors

Description: The US Heavy Ion Fusion Virtual National Laboratory is continuing research into ion sources and injectors that simultaneously provide high current (0.5-1.0 Amps) and high brightness (normalized emittance better than 1.0 {pi}-mm-mr). The central issue of focus is whether to continue pursuing the traditional approach of large surface ionization sources or to adopt a multiaperture approach that transports many smaller ''beamlets'' separately at low energies before allowing them to merge. For the l… more
Date: May 24, 2002
Creator: Ahle, Larry; Grote, Dave & Kwan, Joe
Partner: UNT Libraries Government Documents Department
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Progress in the development of superconducting quadrupoles for heavy ion fusion

Description: The Heavy Ion Fusion program is developing single aperture superconducting quadrupoles based on NbTi conductor, for use in the High Current Experiment at Lawrence Berkeley National Laboratory. Following the fabrication and testing of prototypes using two different approaches, a baseline design has been selected and further optimized. A prototype cryostat for a quadrupole doublet, with features to accommodate induction acceleration modules, is being fabricated. The single aperture magnet was der… more
Date: May 24, 2002
Creator: Faltens, A.; Lietzke, A.; Sabbi, G.; Seidl, P.; Lund, S.; Manahan, B. et al.
Partner: UNT Libraries Government Documents Department
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Design and Testing of a Fast, 50 kV Solid-State Kicker Pulser

Description: The ability to extract particle beam bunches from a ring accelerator in arbitrary order can greatly extend an accelerator's capabilities and applications. A prototype solid-state kicker pulser capable of generating asynchronous bursts of 50 kV pulses has been designed and tested into a 50{Omega} load. The pulser features fast rise and fall times and is capable of generating an arbitrary pattern of pulses with a maximum burst frequency exceeding 5 MHz If required, the pulse-width of each pulse i… more
Date: June 24, 2002
Creator: Cook, E. G.; Hickman, B. C.; Lee, B. S.; Hawkins, S. A.; Gower, E. J.; Allen, F. V. et al.
Partner: UNT Libraries Government Documents Department
open access

A Composite Target Concept for Multi-Pulse Radiography

Description: Multi-pulse radiographic accelerators, such as the DARHT-II facility under construction at Los Alamos National Laboratory, generate X-rays by striking a solid, high-Z ''bremsstrahlung converter target'' with a tightly focused, high-current, relativistic electron beam. In the process, the converter target is heated to a plasma state and significant thermal expansion can occur during the interval between pulses, depleting the beam focus region of target material and reducing the X-ray output. Bea… more
Date: June 4, 2002
Creator: McCarrick, J
Partner: UNT Libraries Government Documents Department
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Synthesizing a four-dimensional beam particle distribution frommultiple two-dimensional views

Description: The transverse dynamics of a nearly-monoenergetic particle beam are described by the evolution of the 4D distribution f(x,y,x',y'), where x and y are the transverse spatial coordinates and x' {triple_bond} p{sub x}/p{sub z} and y' {triple_bond} p{sub y}/p{sub z} are the corresponding momentum components divided by the longitudinal momentum component. In present-day experimental practice, such beams are often diagnosed by passing them through an axially-separated pair of slits parallel to the y … more
Date: February 20, 2002
Creator: Friedman, A.; Grote, D. P.; Celata, C. M. & Staples, J. W.
Partner: UNT Libraries Government Documents Department
open access

Advanced visualization technology for terascale particle accelerator simulations

Description: This paper presents two new hardware-assisted rendering techniques developed for interactive visualization of the terascale data generated from numerical modeling of next generation accelerator designs. The first technique, based on a hybrid rendering approach, makes possible interactive exploration of large-scale particle data from particle beam dynamics modeling. The second technique, based on a compact texture-enhanced representation, exploits the advanced features of commodity graphics card… more
Date: November 16, 2002
Creator: Ma, K-L; Schussman, G.; Wilson, B.; Ko, K.; Qiang, J. & Ryne, R.
Partner: UNT Libraries Government Documents Department
open access

Electron cloud effects in intense, ion beam linacs theory and experimental planning for heavy-ion fusion

Description: Heavy-ion accelerators for HIF will operate at high aperture-fill factors with high beam current and long pulses. This will lead to beam ions impacting walls: liberating gas molecules and secondary electrons. Without special preparation a large fractional electron population ({approx}>1%) is predicted in the High-Current Experiment (HCX), but wall conditioning and other mitigation techniques should result in substantial reduction. Theory and particle-in-cell simulations suggest that electron… more
Date: May 21, 2002
Creator: Molvik, A.W.; Cohen, R.H.; Lund, S.M.; Bieniosek, F.M.; Lee, E.P.; Prost, L.R. et al.
Partner: UNT Libraries Government Documents Department
open access

Modeling of Capillary Discharge Plasma for X-Ray Lasers, XUV Lithography and Other Applications

Description: It is long ago recognized that Z-pinches represent very natural medium for x-ray lasers (XRL) due to its favorable geometry and achievable high densities and temperatures. They also are very efficient x-ray sources. One of their variants, the capillary discharges, attracted attention of plasma physics researchers for almost two decades. It has been used for hot dense plasma formation and x-ray lasers[1,2], for transportation of laser beams and XUV radiation generation in x-ray lithography[3,4],… more
Date: October 22, 2002
Creator: Shlyaptsev, V. N.; Dunn, J.; Moon, S. J.; Fournier, K. B.; Osterheld, A. L.; Rocca, J. J. et al.
Partner: UNT Libraries Government Documents Department
open access

Accurate estimation of the RMS emittance from single current amplifier data

Description: This paper presents the SCUBEEx rms emittance analysis, a self-consistent, unbiased elliptical exclusion method, which combines traditional data-reduction methods with statistical methods to obtain accurate estimates for the rms emittance. Rather than considering individual data, the method tracks the average current density outside a well-selected, variable boundary to separate the measured beam halo from the background. The average outside current density is assumed to be part of a uniform ba… more
Date: May 31, 2002
Creator: Stockli, Martin P.; Welton, R. F.; Keller, R.; Letchford, A. P.; Thomae, R. W. & Thomason, J. W. G.
Partner: UNT Libraries Government Documents Department
open access

Mesh refinement for particle-in-cell plasma simulations: Applications to - and benefits for - heavy ion fusion

Description: The numerical simulation of the driving beams in a heavy ion fusion power plant is a challenging task, and simulation of the power plant as a whole, or even of the driver, is not yet possible. Despite the rapid progress in computer power, past and anticipated, one must consider the use of the most advanced numerical techniques, if they are to reach the goal expeditiously. One of the difficulties of these simulations resides in the disparity of scales, in time and in space, which must be resolve… more
Date: May 24, 2002
Creator: Vay, J. L.; Colella, P.; McCorquodale, P.; Van Straalen, B.; Friedman, A. & Grote, D. P.
Partner: UNT Libraries Government Documents Department
open access

Neutron Emission Characteristics of a High-Current Plasma Focus: Initial Studies

Description: The Texas A and M University plasma focus machine is operational and is beginning to provide good experimental data. It has its origins in several earlier machines and is located in a former service station building with a shield wall that provides a good geometry for neutron measurements. We are operating in the high pressure mode for a plasma focus, similar to previous efforts in the US. Early neutron measurements are providing some insight for the machine's operation.
Date: June 1, 2002
Creator: Ziegler, L. H.; Freeman, B. L. & Boydston, J. C.
Partner: UNT Libraries Government Documents Department
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