Simulating timedependent energy transfer between crossed laser beams in an expanding plasma
Abstract
A coupled mode system is derived to investigate a threewave parametric instability leading to energy transfer between copropagating laser beams crossing in a plasma flow. The model includes beams of finite width refracting in a prescribed transverse plasma flow with spatial and temporal gradients in velocity and density. The resulting paraxial light equations are discretized spatially with a CrankNicholsontype scheme, and these algebraic constraints are nonlinearly coupled with ordinary differential equations in time that describe the ion acoustic response. The entire nonlinear differentialalgebraic system is solved using an adaptive, backwarddifferencing method coupled with Newton's method. A numerical study is conducted in two dimensions that compares the intensity gain of the fully timedependent coupled mode system with the gain computed under the further assumption of a strongly damped ion acoustic response. The results demonstrate a timedependent gain suppression when the beam diameter is commensurate with the velocity gradient scale length. The gain suppression is shown to depend on timedependent beam refraction and is interpreted as a timedependent frequency shift.
 Authors:
 Center for Applied Scientific Computing, L561, Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 945510808 (United States). Email: hittinger1@llnl.gov
 Center for Applied Scientific Computing, L561, Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 945510808 (United States). Email: dorr1@llnl.gov
 AX Division, L038, Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 945510808 (United States). Email: berger5@llnl.gov
 AX Division, L038, Lawrence Livermore National Laboratory, PO Box 808, Livermore, CA 945510808 (United States). Email: williams16@llnl.gov
 Publication Date:
 OSTI Identifier:
 20687263
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Journal of Computational Physics; Journal Volume: 209; Journal Issue: 2; Other Information: DOI: 10.1016/j.jcp.2005.03.024; PII: S00219991(05)001944; Copyright (c) 2005 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ALGORITHMS; BRILLOUIN EFFECT; COMPARATIVE EVALUATIONS; ENERGY TRANSFER; LASERS; NEWTON METHOD; NONLINEAR PROBLEMS; NUMERICAL ANALYSIS; PARAMETRIC INSTABILITIES; PLASMA; REFRACTION; TIME DEPENDENCE; WAVE EQUATIONS
Citation Formats
Hittinger, J.A.F., Dorr, M.R., Berger, R.L., and Williams, E.A. Simulating timedependent energy transfer between crossed laser beams in an expanding plasma. United States: N. p., 2005.
Web. doi:10.1016/j.jcp.2005.03.024.
Hittinger, J.A.F., Dorr, M.R., Berger, R.L., & Williams, E.A. Simulating timedependent energy transfer between crossed laser beams in an expanding plasma. United States. doi:10.1016/j.jcp.2005.03.024.
Hittinger, J.A.F., Dorr, M.R., Berger, R.L., and Williams, E.A. Tue .
"Simulating timedependent energy transfer between crossed laser beams in an expanding plasma". United States.
doi:10.1016/j.jcp.2005.03.024.
@article{osti_20687263,
title = {Simulating timedependent energy transfer between crossed laser beams in an expanding plasma},
author = {Hittinger, J.A.F. and Dorr, M.R. and Berger, R.L. and Williams, E.A.},
abstractNote = {A coupled mode system is derived to investigate a threewave parametric instability leading to energy transfer between copropagating laser beams crossing in a plasma flow. The model includes beams of finite width refracting in a prescribed transverse plasma flow with spatial and temporal gradients in velocity and density. The resulting paraxial light equations are discretized spatially with a CrankNicholsontype scheme, and these algebraic constraints are nonlinearly coupled with ordinary differential equations in time that describe the ion acoustic response. The entire nonlinear differentialalgebraic system is solved using an adaptive, backwarddifferencing method coupled with Newton's method. A numerical study is conducted in two dimensions that compares the intensity gain of the fully timedependent coupled mode system with the gain computed under the further assumption of a strongly damped ion acoustic response. The results demonstrate a timedependent gain suppression when the beam diameter is commensurate with the velocity gradient scale length. The gain suppression is shown to depend on timedependent beam refraction and is interpreted as a timedependent frequency shift.},
doi = {10.1016/j.jcp.2005.03.024},
journal = {Journal of Computational Physics},
number = 2,
volume = 209,
place = {United States},
year = {Tue Nov 01 00:00:00 EST 2005},
month = {Tue Nov 01 00:00:00 EST 2005}
}

A coupled mode system is derived to investigate a threewave parametric instability leading to energy transfer between copropagating laser beams crossing in a plasma flow. The model includes beams of finite width refracting in a prescribed transverse plasma flow with spatial and temporal gradients in velocity and density. The resulting paraxial light equations are discretized spatially with a CrankNicholsontype scheme, and these algebraic constraints are nonlinearly coupled with ordinary differential equations in time that describe the ion acoustic response. The entire nonlinear differentialalgebraic system is solved using an adaptive, backwarddifferencing method coupled with Newton's method. A numerical study is conductedmore »

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