Bochum 2015 – scientific programme
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P: Fachverband Plasmaphysik
P 28: Laser Plasmas II
P 28.1: Talk
Thursday, March 5, 2015, 16:30–16:45, HZO 50
Direct measurement of electron’s dephasing in a laser-driven wakefield — •D. E. Cardenas1,2, S. W. Chou1,2, J. Xu1,3, A. Buck1,2, K. Schmid1,2, C. M. S. Sears1, B. Sheng3, F. Krausz1,2, and L. Veisz1 — 1Max-Planck-Institute für Quantenoptik, Hans-Kopfermann Strasse 1, 85748, Garching, Germany — 2Ludwig-Maximilians-Universität, Am Couloumbwall 1, 85748, Garching, Germany — 3State Key Laboratory of High Field Laser Physics, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P. O. Box 800-211, Shanghai 201800, China
One of the most important effects limiting the maximal achievable energy of a laser-wakefield-accelerated electron [1] is dephasing. This process limits the acceleration length to a distance an electron must propagate in the lab system until it outruns the plasma wave by half of the plasma wavelength, i.e. the dephasing length Ld ≈ λp3/λ02, where λp and λ0 are the plasma and laser wavelength, respectively [2]. In resonant conditions, the laser pulse duration should match half of the plasma wavelength. Using the pulses delivered by the <5 fs Light Wave Synthesizer 20 (LWS-20) and the 8 fs LWS-10 [3], dephasing lengths in the order of 100 µ m become measureable using shock-front injection [4]. These results match quite well the linear theory and give a solid basis to design higher energy accelerators using longer laser pulses. [1] T. Tajima and J.M. Dawson, Phys. Rev. Lett. 43. 267 (1979) [2] E. Esarey, C. B. Schroeder, and W. P. Leemans. Rev. Mod. Phys. 81, 1229. (2009). [3] K. Schmid et al., Phys. Rev. Lett. 102, 124801 (2009) [4] K. Schmid et al., Phys. Rev. ST Accel. Beams 13, 091301 (2010)