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

Journal Article · Thu Jul 07 04:00:00 EDT 2011 · Physics of Plasmas

DOI:https://doi.org/10.1063/1.3609778· OSTI ID:1048294

Schroeder, Carl; Benedetti, Carlo; Esarey, Eric; van Tilborg, Jeroen; Leemans, Wim

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

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: Accelerator& Fusion Research Division
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1048294
• Report Number(s): LBNL-4976E
• Journal Information: Physics of Plasmas, Journal Name: Physics of Plasmas; ISSN PHPAEN; ISSN 1070-664X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
LASERS
MAXWELL EQUATIONS
NUMERICAL SOLUTION
PLASMA
VELOCITY
WAVE EQUATIONS