5-10 May 2019
MedILS
Europe/Berlin timezone

CO2-laser-driven laser-wakefield acceleration experiments at Brookhaven’s Accelerator Test Facility

6 May 2019, 16:00
15m
Main Hall (MedILS)

Main Hall

MedILS

Speaker

Rafal Zgadzaj (University of Texas at Austin)

Description

The advent of chirped-pulse-amplified CO2 lasers [1] has yielded picosecond, long-wavelength infrared (λ=10 μm) laser pulses of terawatt (TW) peak power suitable for driving laser wakefield accelerators (LWFAs) with high ponderomotive force (∼Iλ2) in low-density (1016 cm-3 < ne <1018 cm-3) plasma [2]. Such pulses can drive GeV plasma accelerating structures large enough (λp up to hundreds of μm) to enable precise injection of <1%-energy-spread lepton bunches from external linacs and detailed 4D imaging of wake density [3] and field [4] profiles via optical [3] and electron [4] probing. The AE-71 project at Brookhaven’s Accelerator Test Facility (ATF) is devoted to exploring these opportunities. We report time/space-resolved optical measurements of the electron density structure of self-modulated wakes driven by CO2 laser pulses (4 ps, 0.5 J, focus w0 ≈ 25 μm) [5] in fully self-ionized hydrogen (0.4< ne <3 1018 cm-3) with new experimental and simulation results. Wake amplitude and dynamics were observed by monitoring collective Thomson scattering (CTS) of a co-propagating 532 nm, 4 ps, electronically synchronized probe pulse (jitter ∼200 fs). First- and second-order CTS sidebands, at Δω=±ωp, ±2ωp from the center probe frequency, were observed as a function of pump-probe time delay Δt, plasma density ne, drive laser peak power P, and focus position within the gas jet. SPACE [6] and OSIRIS [7] simulations explain key observations, including unexpected spectral splitting of sidebands at Δt≈0, wake lifetimes of ∼10 ps, and dependence of wake amplitude on ne and P.
[1] M. N. Polyanskiy et al., Optica 2, 675 (2015).
[2] I. Pogorelsky and I. Ben-Zvi, Plasma Phys. Control. Fusion 56, 084017 (2014).
[3] S. P. LeBlanc et al., Phys. Rev. Lett. 77, 5381 (1996).
[4] C. Zhang et al., Plasma Phys. Control. Fusion 60, 044013 (2018).
[5] N. Andreev, Phys. Rev. STAB 6, 041301 (2003).
[6] K. Yu et al., “SPACE code for beam-plasma interaction,” 6th IPAC 2015 (2015).
[7] R.A.Fonseca et al., LNCS (2331) 342, 2002

Working group Laser-driven electron acceleration

Primary authors

Mr James Welch (University of Texas at Austin) L. Amorim (Stonybrook University) Mr Marcus Babzien (Brookhaven National Laboratory) Prof. Michael Downer (University of Texas at Austin) Dr Mikhail Fedurin (Brookhaven National Laboratory) Mr Mael Flament (Stony Brook University) Pietro Iappozutto (Stony Brook Universtiy) Dr Yichao Jing (Brookhaven National Laboratory) Chandrashekhar Joshi (UCLA) Sukho Kongtawong (Stony Brook University) Mr Prabhat Kumar (Stony Brook University) Mr Karl Kusche (Brookhaven National Laboratory) Prof. Vladimir Litvinenko (Stony Brook University) Wei Lu (Tsinghua University) Prof. Warren Mori (UCLA) Dr Mark Palmer (Brookhaven National Laboratory) Dr Igor Pogorelsky (Brookhaven National Laboratory) Dr Mikhail Polyanskiy (Brookhaven National Laboratory) Prof. Roman Samulyak (Stony Brook University) Christina Swinson (Brookhaven National Laboratory) Navid Vafaei-Najafabadi (Stony Brook University) Ms Jiayang Yan (Stony Brook University) Chaojie Zhang (UCLA) Rafal Zgadzaj (University of Texas at Austin)

Presentation Materials