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Title: Thermal effects in plasma-based accelerators

Abstract

Finite plasma temperature can modify the structure of thewake field, reduce the wave-breaking field, and lead to self-trappedelectrons, which can degrade the electron bunch quality in a plasma-basedaccelerator. A relativistic warm fluid theory is used to describe theplasma temperature evolution and alterations to the structure of anonlinear periodic wave exited in a warm plasma. The trapping thresholdfor a plasma electron and the fraction of electrons trapped from athermal distribution are examined using a single-particle model.Numerical artifacts in particle-in-cell models that can mimic the physicsassociated with finite momentum spread are discussed.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Ernest Orlando Lawrence Berkeley NationalLaboratory, Berkeley, CA (US)
Sponsoring Org.:
USDOE Director. Office of Science. High EnergyPhysics
OSTI Identifier:
927386
Report Number(s):
LBNL-63071
R&D Project: 455401; BnR: KA1501020
DOE Contract Number:
DE-AC02-05CH11231
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 14; Journal Issue: 5; Related Information: Journal Publication Date: 2007
Country of Publication:
United States
Language:
English
Subject:
43; laser plasma acceleration

Citation Formats

Esarey, E., Schroeder, C.B., Michel, E., Shadwick, B.A., Geddes,C.G.R., and Leemans, W.P.. Thermal effects in plasma-based accelerators. United States: N. p., 2007. Web. doi:10.1063/1.2714022.
Esarey, E., Schroeder, C.B., Michel, E., Shadwick, B.A., Geddes,C.G.R., & Leemans, W.P.. Thermal effects in plasma-based accelerators. United States. doi:10.1063/1.2714022.
Esarey, E., Schroeder, C.B., Michel, E., Shadwick, B.A., Geddes,C.G.R., and Leemans, W.P.. Tue . "Thermal effects in plasma-based accelerators". United States. doi:10.1063/1.2714022. https://www.osti.gov/servlets/purl/927386.
@article{osti_927386,
title = {Thermal effects in plasma-based accelerators},
author = {Esarey, E. and Schroeder, C.B. and Michel, E. and Shadwick, B.A. and Geddes,C.G.R. and Leemans, W.P.},
abstractNote = {Finite plasma temperature can modify the structure of thewake field, reduce the wave-breaking field, and lead to self-trappedelectrons, which can degrade the electron bunch quality in a plasma-basedaccelerator. A relativistic warm fluid theory is used to describe theplasma temperature evolution and alterations to the structure of anonlinear periodic wave exited in a warm plasma. The trapping thresholdfor a plasma electron and the fraction of electrons trapped from athermal distribution are examined using a single-particle model.Numerical artifacts in particle-in-cell models that can mimic the physicsassociated with finite momentum spread are discussed.},
doi = {10.1063/1.2714022},
journal = {Physics of Plasmas},
number = 5,
volume = 14,
place = {United States},
year = {Tue Jan 09 00:00:00 EST 2007},
month = {Tue Jan 09 00:00:00 EST 2007}
}
  • Finite plasma temperature can modify the structure of the wake field, reduce the wave-breaking field, and lead to self-trapped electrons, which can degrade the electron bunch quality in a plasma-based accelerator. A relativistic warm fluid theory is used to describe the plasma temperature evolution and alterations to the structure of a nonlinear periodic wave exited in a warm plasma. The trapping threshold for a plasma electron and the fraction of electrons trapped from a thermal distribution are examined using a single-particle model. Numerical artifacts in particle-in-cell models that can mimic the physics associated with finite momentum spread are discussed.
  • Plasma-based accelerators can sustain accelerating gradients on the order of 100 GV/m. If the plasma is not fully ionized, fields of this magnitude will ionize neutral atoms via electron tunneling, which can completely change the dynamics of the plasma wake. Particle-in-cell simulations of a high-field plasma wakefield accelerator, using the OOPIC code, which includes field-induced tunneling ionization of neutral Li gas, show that the presence of even moderate neutral gas density significantly degrades the quality of the wakefield. The tunneling ionization model in OOPIC has been validated via a detailed comparison with experimental data from the l'OASIS laboratory. The propertiesmore » of a wake generated directly from a neutral gas are studied, showing that one can recover the peak fields of the fully ionized plasma simulations, if the density of the electron drive bunch is increased such that the bunch rapidly ionized the gas.« less
  • A near-hollow plasma channel, where the plasma density in the channel is much less than the plasma density in the walls, is proposed to provide independent control over the focusing and accelerating forces in a plasma accelerator. In this geometry the low density in the channel contributes to the focusing forces, while the accelerating fields are determined by the high density in the channel walls. The channel also provides guiding for intense laser pulses used for wakefield excitation. Both electron and positron beams can be accelerated in a nearly symmetric fashion. Near-hollow plasma channels can effectively mitigate emittance growth duemore » to Coulomb scattering for high energy physics applications.« less
  • The operational plasma density and laser parameters for future colliders based on laser-plasma accelerators are discussed. Beamstrahlung limits the charge per bunch at low plasma densities. Reduced laser intensity is examined to improve accelerator efficiency in the beamstrahlung-limited regime.
  • A near-hollow plasma channel, where the plasma density in the channel is much less than the plasma density in the walls, is proposed to provide independent control over the focusing and accelerating forces in a plasma accelerator. In this geometry the low density in the channel contributes to the focusing forces, while the accelerating fields are determined by the high density in the channel walls. The channel also provides guiding for intense laser pulses used for wakefield excitation. Both electron and positron beams can be accelerated in a nearly symmetric fashion. Near-hollow plasma channels can effectively mitigate emittance growth duemore » to Coulomb scattering for high-energy physics applications.« less