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Title: Quantitative experiments with electrons in a positively charged beam

Abstract

Intense ion beams are difficult to maintain as non-neutral plasmas. Experiments and simulations are used to study the complex interactions between beam ions and (unwanted) electrons. Such ''electron clouds'' limit the performance of many accelerators. To characterize electron clouds, a number of parameters are measured, including total and local electron production and loss for each of three major sources, beam potential versus time, electron line-charge density, and gas pressure within the beam. Electron control methods include surface treatments to reduce electron and gas emission, and techniques to remove electrons from the beam or block their capture by the beam. Detailed self-consistent simulations include beam-transport fields and electron and gas generation and transport; these compute unexpectedly rich behavior, much of which is confirmed experimentally. For example, in a quadrupole magnetic field, ion and dense electron plasmas interact to produce multi-kV oscillations in the electron plasma and distortions of the beam velocity space distribution, without the system becoming homogeneous or locally neutral.

Authors:
; ; ; ; ; ; ; ; ; ;  [1];  [2]
  1. Heavy-Ion Fusion Science Virtual National Laboratory, Berkeley, California 94720 and Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
  2. (United States)
Publication Date:
OSTI Identifier:
20975080
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Other Information: DOI: 10.1063/1.2436850; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ACCELERATORS; BEAM TRANSPORT; BEAM-PLASMA SYSTEMS; CAPTURE; CHARGE DENSITY; ELECTRONS; ION BEAMS; IONS; MAGNETIC FIELDS; PLASMA; PLASMA DENSITY; PLASMA DIAGNOSTICS; PLASMA SIMULATION; PLASMA WAVES; QUADRUPOLES; SURFACE TREATMENTS

Citation Formats

Molvik, A. W., Kireeff Covo, M., Cohen, R., Friedman, A., Lund, S. M., Sharp, W., Vay, J-L., Baca, D., Bieniosek, F., Leister, C., Seidl, P., and Heavy-Ion Fusion Science Virtual National Laboratory, Berkeley, California 94720 and Lawrence Berkeley National Laboratory, Berkeley, California 94720. Quantitative experiments with electrons in a positively charged beam. United States: N. p., 2007. Web. doi:10.1063/1.2436850.
Molvik, A. W., Kireeff Covo, M., Cohen, R., Friedman, A., Lund, S. M., Sharp, W., Vay, J-L., Baca, D., Bieniosek, F., Leister, C., Seidl, P., & Heavy-Ion Fusion Science Virtual National Laboratory, Berkeley, California 94720 and Lawrence Berkeley National Laboratory, Berkeley, California 94720. Quantitative experiments with electrons in a positively charged beam. United States. doi:10.1063/1.2436850.
Molvik, A. W., Kireeff Covo, M., Cohen, R., Friedman, A., Lund, S. M., Sharp, W., Vay, J-L., Baca, D., Bieniosek, F., Leister, C., Seidl, P., and Heavy-Ion Fusion Science Virtual National Laboratory, Berkeley, California 94720 and Lawrence Berkeley National Laboratory, Berkeley, California 94720. Tue . "Quantitative experiments with electrons in a positively charged beam". United States. doi:10.1063/1.2436850.
@article{osti_20975080,
title = {Quantitative experiments with electrons in a positively charged beam},
author = {Molvik, A. W. and Kireeff Covo, M. and Cohen, R. and Friedman, A. and Lund, S. M. and Sharp, W. and Vay, J-L. and Baca, D. and Bieniosek, F. and Leister, C. and Seidl, P. and Heavy-Ion Fusion Science Virtual National Laboratory, Berkeley, California 94720 and Lawrence Berkeley National Laboratory, Berkeley, California 94720},
abstractNote = {Intense ion beams are difficult to maintain as non-neutral plasmas. Experiments and simulations are used to study the complex interactions between beam ions and (unwanted) electrons. Such ''electron clouds'' limit the performance of many accelerators. To characterize electron clouds, a number of parameters are measured, including total and local electron production and loss for each of three major sources, beam potential versus time, electron line-charge density, and gas pressure within the beam. Electron control methods include surface treatments to reduce electron and gas emission, and techniques to remove electrons from the beam or block their capture by the beam. Detailed self-consistent simulations include beam-transport fields and electron and gas generation and transport; these compute unexpectedly rich behavior, much of which is confirmed experimentally. For example, in a quadrupole magnetic field, ion and dense electron plasmas interact to produce multi-kV oscillations in the electron plasma and distortions of the beam velocity space distribution, without the system becoming homogeneous or locally neutral.},
doi = {10.1063/1.2436850},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}