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Title: Enhanced collective focusing of intense neutralized ion beam pulses in the presence of weak solenoidal magnetic fields

Abstract

In this study, the design of ion drivers for warm dense matter and high energy density physics applications and heavy ion fusion involves transverse focusing and longitudinal compression of intense ion beams to a small spot size on the target. To facilitate the process, the compression occurs in a long drift section filled with a dense background plasma, which neutralizes the intense beam self-fields. Typically, the ion bunch charge is better neutralized than its current, and as a result a net self-pinching (magnetic) force is produced. The self-pinching effect is of particular practical importance, and is used in various ion driver designs in order to control the transverse beam envelope. In the present work we demonstrate that this radial self-focusing force can be significantly enhanced if a weak (B~100 G) solenoidal magnetic field is applied inside the neutralized drift section, thus allowing for substantially improved transport. It is shown that in contrast to magnetic self-pinching, the enhanced collective self-focusing has a radial electric field component and occurs as a result of the overcompensation of the beam charge by plasmaelectrons, whereas the beam current becomes well-neutralized. As the beam leaves the neutralizing drift section, additional transverse focusing can be applied. Formore » instance, in the neutralized drift compression experiments (NDCX) a strong (several Tesla) final focus solenoid is used for this purpose. In the present analysis we propose that the tight final focus in the NDCX experiments may possibly be achieved by using a much weaker (few hundred Gauss) magnetic lens, provided the ion beam carries an equal amount of co-moving neutralizing electrons from the preceding drift section into the lens. In this case the enhanced focusing is provided by the collective electrondynamics strongly affected by a weak applied magnetic field.« less

Authors:
 [1];  [2];  [2];  [2]
  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
  2. Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1248303
Report Number(s):
LLNL-JRNL-517752
Journal ID: ISSN 1070-664X; PHPAEN
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Physics of Plasmas
Additional Journal Information:
Journal Volume: 19; Journal Issue: 5; Journal ID: ISSN 1070-664X
Publisher:
American Institute of Physics (AIP)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION; ion beams; electron beams; magnetic fields; self focusing; electric fields

Citation Formats

Dorf, Mikhail A., Davidson, Ronald C., Kaganovich, Igor D., and Startsev, Edward A. Enhanced collective focusing of intense neutralized ion beam pulses in the presence of weak solenoidal magnetic fields. United States: N. p., 2012. Web. doi:10.1063/1.4722999.
Dorf, Mikhail A., Davidson, Ronald C., Kaganovich, Igor D., & Startsev, Edward A. Enhanced collective focusing of intense neutralized ion beam pulses in the presence of weak solenoidal magnetic fields. United States. https://doi.org/10.1063/1.4722999
Dorf, Mikhail A., Davidson, Ronald C., Kaganovich, Igor D., and Startsev, Edward A. 2012. "Enhanced collective focusing of intense neutralized ion beam pulses in the presence of weak solenoidal magnetic fields". United States. https://doi.org/10.1063/1.4722999. https://www.osti.gov/servlets/purl/1248303.
@article{osti_1248303,
title = {Enhanced collective focusing of intense neutralized ion beam pulses in the presence of weak solenoidal magnetic fields},
author = {Dorf, Mikhail A. and Davidson, Ronald C. and Kaganovich, Igor D. and Startsev, Edward A.},
abstractNote = {In this study, the design of ion drivers for warm dense matter and high energy density physics applications and heavy ion fusion involves transverse focusing and longitudinal compression of intense ion beams to a small spot size on the target. To facilitate the process, the compression occurs in a long drift section filled with a dense background plasma, which neutralizes the intense beam self-fields. Typically, the ion bunch charge is better neutralized than its current, and as a result a net self-pinching (magnetic) force is produced. The self-pinching effect is of particular practical importance, and is used in various ion driver designs in order to control the transverse beam envelope. In the present work we demonstrate that this radial self-focusing force can be significantly enhanced if a weak (B~100 G) solenoidal magnetic field is applied inside the neutralized drift section, thus allowing for substantially improved transport. It is shown that in contrast to magnetic self-pinching, the enhanced collective self-focusing has a radial electric field component and occurs as a result of the overcompensation of the beam charge by plasmaelectrons, whereas the beam current becomes well-neutralized. As the beam leaves the neutralizing drift section, additional transverse focusing can be applied. For instance, in the neutralized drift compression experiments (NDCX) a strong (several Tesla) final focus solenoid is used for this purpose. In the present analysis we propose that the tight final focus in the NDCX experiments may possibly be achieved by using a much weaker (few hundred Gauss) magnetic lens, provided the ion beam carries an equal amount of co-moving neutralizing electrons from the preceding drift section into the lens. In this case the enhanced focusing is provided by the collective electrondynamics strongly affected by a weak applied magnetic field.},
doi = {10.1063/1.4722999},
url = {https://www.osti.gov/biblio/1248303}, journal = {Physics of Plasmas},
issn = {1070-664X},
number = 5,
volume = 19,
place = {United States},
year = {2012},
month = {5}
}

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Works referenced in this record:

Collective Focusing of an Intense Ion Beam
journal, January 1982


Three‐dimensional particle simulation of heavy‐ion fusion beams *
journal, March 1992


Whistler waves produced by a modulated electron beam: Electromagnetic fields in the linear approach
journal, November 1995


Overview of Russian heavy-ion inertial fusion energy program
journal, July 2007


Physics of neutralization of intense high-energy ion beam pulses by electrons
journal, May 2010


Chamber transport
journal, May 2001


Self-pinched transport for ion-driven inertial confinement fusion
journal, November 1996


Beam collimation and transport of quasineutral laser-accelerated protons by a solenoid field
journal, February 2010


Collective focusing of a charge‐neutral ion beam with warm electrons
journal, March 1986


High energy density physics generated by intense heavy ion beams
journal, February 2009


Collective focusing of an intense pulsed ion beam
journal, January 1987


A space-charge-neutralizing plasma for beam drift compression
journal, July 2009

  • Roy, P. K.; Seidl, P. A.; Anders, A.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 606, Issue 1-2, p. 22-30
  • https://doi.org/10.1016/j.nima.2009.03.228

Recent US advances in ion-beam-driven high energy density physics and heavy ion fusion
journal, July 2007

  • Logan, B. G.; Bieniosek, F. M.; Celata, C. M.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 577, Issue 1-2
  • https://doi.org/10.1016/j.nima.2007.02.070

Quasispherical fuel compression and fast ignition in a heavy-ion-driven X-target with one-sided illumination
journal, March 2011


Activities on heavy ion inertial fusion and beam-driven high energy density science in Japan
journal, July 2009

  • Horioka, K.; Kawamura, T.; Nakajima, M.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 606, Issue 1-2
  • https://doi.org/10.1016/j.nima.2009.03.227

Beam dynamics of the Neutralized Drift Compression Experiment-II, a novel pulse-compressing ion accelerator
journal, May 2010


Chamber-transport simulation results for heavy-ion fusion drivers
journal, November 2004


Self-pinched transport of an intense proton beam
journal, January 2000


Intense ion‐beam neutralization in free space
journal, June 1978


Nonlinear charge and current neutralization of an ion beam pulse in a pre-formed plasma
journal, September 2001


Drift Compression of an Intense Neutralized Ion Beam
journal, November 2005


Intense High-Energy Proton Beams from Petawatt-Laser Irradiation of Solids
journal, October 2000


Enhanced Self-Focusing of an Ion Beam Pulse Propagating through a Background Plasma along a Solenoidal Magnetic Field
journal, August 2009


Whistler wave excitation and effects of self-focusing on ion beam propagation through a background plasma along a solenoidal magnetic field
journal, February 2010


Collective focusing of intense ion beam pulses for high-energy density physics applications
journal, March 2011


Observations of the thermalization of the neutralizing electrons in intense ion beams
journal, April 1987


Effects of preneutralization on heavy ion fusion chamber transport
journal, October 2002


Charge and Current Neutralization of an Ion-Beam Pulse Propagating in a Background Plasma along a Solenoidal Magnetic Field
journal, December 2007


Progress in beam focusing and compression for warm-dense matter experiments
journal, July 2009

  • Seidl, P. A.; Anders, A.; Bieniosek, F. M.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 606, Issue 1-2
  • https://doi.org/10.1016/j.nima.2009.03.254

A study of stripped pinched-beam transport for heavy ion fusion
journal, November 1996


Survey of collective instabilities and beam–plasma interactions in intense heavy ion beams
journal, July 2009

  • Davidson, Ronald C.; Dorf, Mikhail A.; Kaganovich, Igor D.
  • Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol. 606, Issue 1-2
  • https://doi.org/10.1016/j.nima.2009.03.077

Streaming instabilities of intense charged particle beams propagating along a solenoidal magnetic field in a background plasma
journal, June 2008


Works referencing / citing this record:

Irradiation of materials with short, intense ion pulses at NDCX-II
journal, May 2017


Sheaths in laboratory and space plasmas
journal, July 2013