Numerical model for plasma electron acceleration in laser wakefield accelerators
- Naval Research Lab., Washington, DC (United States). Plasma Physics Div.
Plasma wakefields produced by a sub-picosecond, high intensity laser pulse in a dense gas jet can accelerate plasma electrons to high energies. The acceleration is believed to be a two stage process in which plasma electrons are accelerated to moderate energies by a low phase velocity wave and then trapped and accelerated by the high phase velocity (v{sub p} {approximately} c), large amplitude wakefield. The laser wakefield accelerator (LFWA) experiment at the Naval Research Laboratory has produced up to 30 MeV electrons with no external injector when operating in the self-modulated regime. The low phase velocity wave in this case could arise from the beating of the laser pump pulse with a wave arising from the backward Raman instability. This interpretation is supported by a numerical model which follows the motion of plasma electrons in analytically-prescribed fields corresponding to the laser pump pulse, the forward-going wakefield, and the Raman waves. The accelerated electrons have a large energy spread and are trapped in several bunches. Esarey, et al. have proposed a scheme which would operate in the standard LWFA regime and employs three collinear laser pulses: the large amplitude pump pulse, a lower amplitude follower pulse at the same frequency, and a counterstreaming colliding pulse at a slightly lower frequency. The interaction between the follower pulse and the colliding pulse produces the first stage of acceleration. The numerical model predicts that if the delay between the pump and follower pulses is optimized, a single short pulse bunch of accelerated plasma electrons with {approximately} 20--30% energy spread can be produced. Even if there is no guiding of the laser pulse, the model predicts that the beam energy can be tens of MeV with a bunch length of tens of femtoseconds.
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Office of Naval Research, Washington, DC (United States)
- OSTI ID:
- 323570
- Report Number(s):
- CONF-970559-; TRN: 99:004288
- Resource Relation:
- Conference: 24. IEEE international conference on plasma science, San Diego, CA (United States), 19-23 May 1997; Other Information: PBD: 1997; Related Information: Is Part Of IEEE conference record -- Abstracts; PB: 354 p.
- Country of Publication:
- United States
- Language:
- English
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