Proton acceleration in a slow wakefield

Journal Article · Mon Jan 09 00:00:00 EST 2017 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4973642· OSTI ID:1465960

Isaacs, Joshua  ^[1]; Sprangle, Phillip ^[2]

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1. Univ. of Maryland, College Park, MD (United States). Dept. of Physics. Inst. for Research in Electronics and Applied Physics
2. Univ. of Maryland, College Park, MD (United States). Dept. of Physics. Inst. for Research in Electronics and Applied Physics. Dept. of Electrical Engineering; Naval Research Lab. (NRL), Washington, DC (United States). Plasma Physics Division

In this paper, we propose and analyze a mechanism to accelerate protons in a low-phase-velocity wakefield. The wakefield is shock-excited by the interaction of two counter-propagating laser pulses in a plasma density gradient. The laser pulses consist of a forward-propagating short pulse (less than a plasma period) and a counter-propagating long pulse. The beating of these pulses generates a slow forward-propagating wakefield that can trap and accelerate protons. The trapping and acceleration is accomplished by appropriately tapering both the plasma density and the amplitude of the backward-propagating pulse. An example is presented in which the trapping and accelerating wakefield has a phase velocity varying from $V_{\mathit{p}\mathit{h}}\approx 0$ to $\approx 0.15c(~10\text{MeV}\text{proton}\text{energy})$ over a distance of ~1 cm. The required laser intensities, pulse durations, pulse energies, and plasma densities are relatively modest. Instabilities such as the Raman instability are mitigated because of the large plasma density gradients. Finally, numerical solutions of the wakefield equation and simulations using turboWAVE are carried out to support our model.

• Research Organization: Univ. of Maryland, College Park, MD (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: SC0015516
• OSTI ID: 1465960
• Alternate ID(s): OSTI ID: 1361727
• Journal Information: Applied Physics Letters, Vol. 110, Issue 2; ISSN 0003-6951
• Publisher: American Institute of Physics (AIP)
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
kinematics
protons
chirping
plasma instabilities
laser plasma interactions
plasma waves
plasma density
electric fields
nonlinear dynamics