Space Charge Effects in a Bending Magnet System

Laser and Particle Beams, 2002

Between the accelerator and fusion chamber, the heavy ion beams are subject to a dramatic but vital series of manipulations, some of which are carried out simultaneously and involve large space charge forces. The…

2008

The purpose of this course is to provide a comprehensive introduction to the physics of beams with intense space charge. This course is suitable for graduate students and researchers interested in accelerator systems that require sufficient high intensity where mutual particle interactions in the beam can no longer be neglected. Prerequisites: undergraduate level Electricity and Magnetism and Classical Mechanics. Some familiarity with plasma physics, special relativity, and basic accelerator physics is recommended but not required. Objectives This course is intended to give the student a broad overview of the dynamics of beams with strong space charge. The emphasis is on theoretical and analytical methods of describing the acceleration and transport of beams. Some aspects of numerical and experimental methods will also be covered. Students will become familiar with standard methods employed to understand the transverse and longitudinal evolution of beams with strong space charge. The material covered will provide a foundation to design practical architectures. Instructional Method Lectures will be given during morning sessions, followed by afternoon discussion sessions, which will engage the student on the material covered in lecture. Daily problem sets will be assigned that will be 2 of 2 06/06/2008 09:56 PM waste transmutation, etc. Reading Requirements Extensive class notes will be provided that will serve as the primary reference.

Il Nuovo Cimento A, 1993

A two-year study of recirculating induction heavy ion accelerators as low-cost driver for inertial-fusion energy applications was recently completed. The projected cost of a 4 MJ accelerator was estimated to be about $500 M (million) and the efficiency was estimated to be 35%. The principal technology issues include energy recovery of the ramped dipole magnets, which is achieved through use of ringing inductive/capacitive circuits, and high repetition rates of the induction cell pulsers, which is accomplished through arrays of field effect transistor (FET) switches. Principal physics issues identified include minimization of particle loss from interactions with the background gas, and more demanding emittance growth and centroid control requirements associated with the propagation of space-charge-dominated beams around bends and over large path lengths. In addition, instabilities such as the longitudinal resistive instability, beam-breakup instability and betatron-orbit instability were found to be controllable with careful design.

1990

A simple transport code has been developed to model the beam in a heavy-ion recirculating accelerator. The novel feature of the model is the treatment of the beam charge density as a Lagrangian fluid in the axial direction. In addition, the envelope and centroid equations include terms that account for the transverse self-force, image forces, and bend fields in the paraxial limit. The use of "compressible" beam slices makes the code suitable for designing the acceleration and compression schedules. The code has been used primarily to design the lattice of the LLNL recirculator, and preliminary transport results for that machine are presented here.

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 2001

An overview of experiments is presented, in which the physical dimensions, emittance and perveance are scaled to explore driver-relevant beam dynamics. Among these are beam merging, focusing to a small spot, and bending and recirculating beams. The Virtual National Laboratory for Heavy Ion Fusion (VNL) is also developing two driver-scale beam experiments involving heavy-ion beams with I(sub beam) ~; 1 Ampere to provide guidance for the design of an Integrated Research Experiment (IRE) for driver system studies within the next 5 years. Multiple-beam sources and injectors are being designed and a one-beam module will be built and tested. Another experimental effort will be the transport of such a beam through ~;100 magnetic quadrupoles. The experiment will determine transport limits at high aperture fill factors, beam halo formation, and the influence on beam properties of secondary electron Research into driver technology will be briefly presented, including the development of ferromagnetic core materials, induction core pulsers, multiple-beam quadrupole arrays and plasma channel formation experiments for pinched transport in reactor chambers.

Il Nuovo Cimento A, 1993

has proposed building a 10 MeV Induction Linac Systems Experiment, ILSE, to investigate accelerator physics and beam manipulations which are needed or desirable for an induction linac driver. This paper describes the experiments proposed for ILSE: transverse beam combining, drift compression, bending of space-charge-dominated beams, final focus, recirculation, and some studies of beam propagation in the environment of fF, e reacT_or chamber.

1994

A series of small-scale experiments has been proposed to study critical physics issues of a circular induction accelerator for heavy-ion fusion. Because the beam dynamics will be dominated by space charge, the experiments require careful design of the lattice and acceleration schedule. A hierarchy of codes has been developed for modeling the experiments at different levels of detail. The codes

Nuovo Cimento a Nucl Part F, 1993

A multi-dimensional discrete-particle simulation code, WARP, and its application to heavy-ion fusion beams is described. The code's 3D package combines features of an accelerator code and a particle-in-cell plasma simulation, and can efficiently track beams through many lattice elements and around bends. The code's r, z package allows one to follow beams over very long times and models the accelerating module impedances. A number of applications are presented. These have led to an improved understanding of: beam equilibria, and the approach to equilibrium; longitudinal beam dynamics and stability; electrostatic quadrupole (ESQ) injector aberrations; bending and recirculation of space-charge--dominated beams; and the drift-compression process. The code is being used for accelerator design, as well as for theoretical investigations.

1998

Thisisapreprintofapaperintendedforpublicationinajoumalorproceedings Since changes may be made before publication, this preprint is made available with the. understanding that it will not be cited or reproduced without the permission of the author .

Physical Review Special Topics - Accelerators and Beams, 2013

We describe near-term heavy ion fusion (HIF) research objectives associated with developing an inertial fusion energy demonstration power plant. The goal of this near-term research is to lay the essential groundwork for an intermediate research experiment (IRE), designed to demonstrate all the key driver beam manipulations at a meaningful scale, and to enable HIF relevant target physics experiments. This is a very large step in size and complexity compared to HIF experiments to date, and if successful, it would justify proceeding to a demonstration fusion power plant. With an emphasis on accelerator research, this paper is focused on the most important near-term research objectives to justify and to reduce the risks associated with the IRE. The chosen time scale for this research is 5-10 years, to answer key questions associated with the HIF accelerator drivers, in turn enabling a key decision on whether to pursue a much more ambitious and focused inertial fusion energy research and development program. This is consistent with the National Academies of Sciences Review of Inertial Fusion Energy Systems Interim Report, which concludes that ''it would be premature at the present time to choose a particular driver approach.. .'' and encouraged the continued development of community consensus on critical issues, and to develop ''options for a community-based roadmap for the development of inertial fusion as a practical energy source.''