Title: Ultrabright Electron Bunch Injection in a Plasma Wakefield Driven by a Superluminal Flying Focus Electron Beam

Abstract

Here, we propose a new method for self-injection of high-quality electron bunches in the plasma wakefield structure in the blowout regime utilizing a “flying focus” produced by a drive beam with an energy chirp. In a flying focus the speed of the density centroid of the drive bunch can be superluminal or subluminal by utilizing the chromatic dependence of the focusing optics. We first derive the focal velocity and the characteristic length of the focal spot in terms of the focal length and an energy chirp. We then demonstrate using multidimensional particle-in-cell simulations that a wake driven by a superluminally propagating flying focus of an electron beam can generate GeV-level electron bunches with ultralow normalized slice emittance (~30 nm rad), high current (~17 kA), low slice energy spread (~0.1%), and therefore high normalized brightness (> 10¹⁹ A/ m² /rad²) in a plasma of density ~10¹⁹ cm^–3. The injection process is highly controllable and tunable by changing the focal velocity and shaping the drive beam current. Nearterm experiments at FACET II where the capabilities to generate tens of kA, < 10 fs drivers are planned, could potentially produce beams with brightness near 10²⁰ A / m² / rad².

Authors:

Li, F.  ^[1];

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• Search DOE PAGES for ORCID "0000-0001-8627-910X"

Dalichaouch, T.  N.  ^[1];

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• Search DOE PAGES for ORCID "0000-0002-4735-0150"

Pierce, J.  R. ^[1]; Xu, X.  ^[2];

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• Search DOE PAGES for ORCID "0000-0001-9247-151X"

Tsung, F.  S. ^[1]; Lu, W. ^[3]; Joshi, C. ^[1]; Mori, W.  B.  ^[1]

• Search DOE PAGES for author "Mori, W.  B."
• Search DOE PAGES for ORCID "0000-0002-6394-5082"

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+ Show Author Affiliations

1. Univ. of California, Los Angeles, CA (United States)
2. SLAC National Accelerator Lab., Menlo Park, CA (United States)
3. Tsinghua Univ., Beijing (China)

Publication Date:

Fri Apr 29 00:00:00 EDT 2022

Research Org.:

SLAC National Accelerator Lab., Menlo Park, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR). Scientific Discovery through Advanced Computing (SciDAC); National Science Foundation (NSF)

OSTI Identifier:

1871596

Alternate Identifier(s):

OSTI ID: 1866143

Grant/Contract Number:  

AC02-76SF00515; 644405; SC0010064; 1806046; 2003354

Resource Type:

Accepted Manuscript

Journal Name:

Physical Review Letters

Additional Journal Information:

Journal Volume: 128; Journal Issue: 17; Journal ID: ISSN 0031-9007

Publisher:

American Physical Society (APS)

Country of Publication:

United States

Language:

English

Subject:

70 PLASMA PHYSICS AND FUSION TECHNOLOGY