Group velocity and pulse lengthening of mismatched laser pulses in plasma channels

Journal Article · Mon Aug 15 04:00:00 EDT 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3609778· OSTI ID:22043421

Schroeder, C B; Benedetti, C; Esarey, E; Tilborg, J van; Leemans, W P ^[1]

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1. Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

Analytic solutions are presented to the non-paraxial wave equation describing an ultra-short, low-power, laser pulse propagating in a plasma channel. Expressions for the laser pulse centroid motion and laser group velocity are derived, valid for matched and mismatched propagation in a parabolic plasma channel, as well as in vacuum, for an arbitrary Laguerre-Gaussian laser mode. The group velocity of a mismatched laser pulse, for which the laser spot size is strongly oscillating, is found to be independent of propagation distance and significantly less than that of a matched pulse. Laser pulse lengthening of a mismatched pulse owing to laser mode slippage is examined and found to dominate over that due to dispersive pulse spreading for sufficiently long pulses. Analytic results are shown to be in excellent agreement with numerical solutions of the full Maxwell equations coupled to the plasma response. Implications for plasma channel diagnostics are discussed.

• OSTI ID: 22043421
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas Journal Issue: 8 Vol. 18; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
ANALYTICAL SOLUTION
LASER RADIATION
LIGHT TRANSMISSION
MAXWELL EQUATIONS
MODULATION
NONLINEAR OPTICS
NUMERICAL SOLUTION
PLASMA
PULSES
WAVE EQUATIONS