Year: 2020
Type: article
Abstract: A plasma channel created by the combination of a capillary discharge and inverse Bremsstrahlung laser heating enabled the generation of electron bunches with energy up to 7.8 GeV in a laser-driven plasma accelerator. The capillary discharge created an initial plasma channel and was used to tune the plasma temperature, which optimized laser heating. Although optimized colder initial plasma temperatures reduced the ionization degree, subsequent ionization from the heater pulse created a fully ionized plasma on-axis. The heater pulse duration was chosen to be longer than the hydrodynamic timescale of ≈1 ns, such that later temporal slices were more efficiently guided by the channel created by the front of the pulse. Simulations are presented which show that this thermal self-guiding of the heater pulse enabled channel formation over 20 cm. The post-heated channel had lower on-axis density and increased focusing strength compared to relying on the discharge alone, which allowed for guiding of relativistically intense laser pulses with a peak power of 0.85 PW and wakefield acceleration over 15 diffraction lengths. Electrons were injected into the wake in multiple buckets and times, leading to several electron bunches with different peak energies. To create single electron bunches with low energy spread, experiments using localized ionization injection inside a capillary discharge waveguide were performed. A single injected bunch with energy 1.6 GeV, charge 38 pC, divergence 1 mrad, and relative energy spread below 2% full-width half-maximum was produced in a 3.3 cm-long capillary discharge waveguide. This development shows promise for mitigation of energy spread and future high efficiency staged acceleration experiments.
Source: Physics of Plasmas
DOI: 10.1063/5.0002769
Authors: A. J. Gonsalves, K. Nakamura, C. Benedetti, C. V. Pieronek, S. Steinke, J. H. Bin, S. S. Bulanov, J. van Tilborg, C. G. R. Geddes, C. B. Schroeder, J. Daniels, Cs. Tóth, L. Obst-Huebl, R. G. W. van den Berg, G. Bagdasarov, N. Bobrova, V. Gasilov, G. Korn, P. Sasorov, W. P. Leemans, E. Esarey
Language: English
Subfield: Nuclear and High Energy Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: G1010664878, G122673668, G1286236842, G1677143136, G176604203, G1863003419, G222768804, G291036901, G3083819904, G340888770, G3490171961, G3562095311, G3689434148, G419881185, G4280972364, G42916606, G4501827968, G498139845, G5076365615, G5916014575, G6652958823, From Phase Space Manipulation to First Light from a Laser Plasma Accelerator Powered Free Electron Laser, G759921648, G8066294080, G969889393
OpenAlex ID: W3021950260