skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Longitudinal profiles of plasma parameters in a laser-ignited capillary discharge and implications for laser wakefield accelerator applications

Abstract

The evolution of longitudinal electron density and temperature profiles in plasma channel produced by a low-current Plexiglas capillary discharge with laser ignition was investigated by spectroscopic methods. The plasma was produced by an electric discharge using a 0.5 mm diameter, 15 mm long Plexiglas capillary. The electron density measured in near-outlet region was found to be lower by 30%. Simulations show that this variation of the plasma density near the entrance of the capillary can pose substantial difficulties for external injection of electrons for laser wakefield accelerator applications.

Authors:
; ; ; ; ; ; ; ;  [1];  [2];  [2];  [2];  [2];  [2]
  1. Racah Institute of Physics, Hebrew University, Jerusalem (Israel)
  2. (United States)
Publication Date:
OSTI Identifier:
20776921
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 87; Journal Issue: 26; Other Information: DOI: 10.1063/1.2149183; (c) 2005 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; CAPILLARIES; ELECTRIC DISCHARGES; ELECTRON DENSITY; ELECTRON TEMPERATURE; ION TEMPERATURE; LASERS; LIGHT TRANSMISSION; PLASMA; PLASMA DENSITY; PLASMA DIAGNOSTICS; PLASMA SIMULATION; PLEXIGLAS; WAKEFIELD ACCELERATORS

Citation Formats

Levin, M., Pukhov, A., Hubbard, R.F., Kaganovich, D., Gordon, D.F., Sprangle, P., Ting, A., Hafizi, B., Zigler, A., Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, LET Corporation, 4407 McArthur Boulevard, Washington, DC 20007, Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, Icarus Research Inc., P.O. Box 30780, Bethesda, Maryland 20824, and Racah Institute of Physics, Hebrew University, Jerusalem, Israel and Icarus Research Inc., P.O. Box 30780, Bethesda, Maryland 20824. Longitudinal profiles of plasma parameters in a laser-ignited capillary discharge and implications for laser wakefield accelerator applications. United States: N. p., 2005. Web. doi:10.1063/1.2149183.
Levin, M., Pukhov, A., Hubbard, R.F., Kaganovich, D., Gordon, D.F., Sprangle, P., Ting, A., Hafizi, B., Zigler, A., Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, LET Corporation, 4407 McArthur Boulevard, Washington, DC 20007, Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, Icarus Research Inc., P.O. Box 30780, Bethesda, Maryland 20824, & Racah Institute of Physics, Hebrew University, Jerusalem, Israel and Icarus Research Inc., P.O. Box 30780, Bethesda, Maryland 20824. Longitudinal profiles of plasma parameters in a laser-ignited capillary discharge and implications for laser wakefield accelerator applications. United States. doi:10.1063/1.2149183.
Levin, M., Pukhov, A., Hubbard, R.F., Kaganovich, D., Gordon, D.F., Sprangle, P., Ting, A., Hafizi, B., Zigler, A., Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, LET Corporation, 4407 McArthur Boulevard, Washington, DC 20007, Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375, Icarus Research Inc., P.O. Box 30780, Bethesda, Maryland 20824, and Racah Institute of Physics, Hebrew University, Jerusalem, Israel and Icarus Research Inc., P.O. Box 30780, Bethesda, Maryland 20824. Mon . "Longitudinal profiles of plasma parameters in a laser-ignited capillary discharge and implications for laser wakefield accelerator applications". United States. doi:10.1063/1.2149183.
@article{osti_20776921,
title = {Longitudinal profiles of plasma parameters in a laser-ignited capillary discharge and implications for laser wakefield accelerator applications},
author = {Levin, M. and Pukhov, A. and Hubbard, R.F. and Kaganovich, D. and Gordon, D.F. and Sprangle, P. and Ting, A. and Hafizi, B. and Zigler, A. and Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 and LET Corporation, 4407 McArthur Boulevard, Washington, DC 20007 and Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 and Icarus Research Inc., P.O. Box 30780, Bethesda, Maryland 20824 and Racah Institute of Physics, Hebrew University, Jerusalem, Israel and Icarus Research Inc., P.O. Box 30780, Bethesda, Maryland 20824},
abstractNote = {The evolution of longitudinal electron density and temperature profiles in plasma channel produced by a low-current Plexiglas capillary discharge with laser ignition was investigated by spectroscopic methods. The plasma was produced by an electric discharge using a 0.5 mm diameter, 15 mm long Plexiglas capillary. The electron density measured in near-outlet region was found to be lower by 30%. Simulations show that this variation of the plasma density near the entrance of the capillary can pose substantial difficulties for external injection of electrons for laser wakefield accelerator applications.},
doi = {10.1063/1.2149183},
journal = {Applied Physics Letters},
number = 26,
volume = 87,
place = {United States},
year = {Mon Dec 26 00:00:00 EST 2005},
month = {Mon Dec 26 00:00:00 EST 2005}
}
  • Cited by 1
  • Gas-filled capillary discharge waveguides are commonly used as media for plasma wakefield accelerators. We show that effective waveguides can be manufactured using a femtosecond laser micromachining technique to produce a linearly tapered plasma density, which enables the energy of the accelerator to be enhanced significantly. A laser guiding efficiency in excess of 82% at sub-relativistic intensities has been demonstrated in a 40 mm long capillary with a diameter tapering from 320 {mu}m to 270 {mu}m, which gives rise to an on-axis, time-averaged plasma density that varies from 1.0 x 10{sup 18} cm{sup -3} to 1.6 x 10{sup 18} cm{sup -3}.
  • We demonstrated the production of an optical waveguide in a capillary discharge-produced plasma using a cylindrical capillary. Plasma parameters of its waveguide were characterized by use of both a Nomarski laser interferometer and a hydrogen plasma line spectrum. A space-averaged maximum temperature of 3.3 eV with electron densities of the order of 10{sup 17} cm{sup -3} was observed at a discharge time of 150 ns and a maximum discharge current of 400 A. An ultrashort, intense laser pulse was guided by use of this plasma channel.
  • Via three-dimensional particle-in-cell simulations, the self-mode-transition of a laser-driven electron acceleration from laser wakefield to plasma-wakefield acceleration is studied. In laser wakefield accelerator (LWFA) mode, an intense laser pulse creates a large amplitude wakefield resulting in high-energy electrons. Along with the laser pulse depletion, the electron bunch accelerated in the LWFA mode drives a plasma wakefield. Then, after the plasma wakefield accelerator mode is established, electrons are trapped and accelerated in the plasma wakefield. The mode transition process and the characteristics of the accelerated electron beam are presented.
  • The role of the gas/plasma plume at the entrance of a gas-filled capillary discharge plasma waveguide in increasing the laser intensity has been investigated. Distinction is made between neutral gas and hot plasma plumes that, respectively, develop before and after discharge breakdown. Time-averaged measurements show that the on-axis plasma density of a fully expanded plasma plume over this region is similar to that inside the waveguide. Above the critical power, relativistic and ponderomotive self-focusing lead to an increase in the intensity, which can be nearly a factor of 2 compared with the case without a plume. When used as amore » laser plasma wakefield accelerator, the enhancement of intensity can lead to prompt electron injection very close to the entrance of the waveguide. Self-focusing occurs within two Rayleigh lengths of the waveguide entrance plane in the region, where the laser beam is converging. Analytical theory and numerical simulations show that, for a density of 3.0 × 10{sup 18} cm{sup −3}, the peak normalized laser vector potential, a{sub 0}, increases from 1.0 to 1.85 close to the entrance plane of the capillary compared with a{sub 0} = 1.41 when the plume is neglected.« less