Group velocity and pulse lengthening of mismatched laser pulses in plasma channels
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:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- Accelerator& Fusion Research Division
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 1048294
- Report Number(s):
- LBNL-4976E; PHPAEN; TRN: US1204160
- Journal Information:
- Physics of Plasmas, Journal Name: Physics of Plasmas; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Similar Records
Nonparaxial propagation of ultrashort laser pulses in plasma channels
Theory and group velocity of ultrashort, tightly focused laser pulses