title: Self-mapping the longitudinal field structure of a nonlinear plasma accelerator cavity.
abstract: The preservation of emittance of the accelerating beam is the next challenge for plasma-based accelerators envisioned for future light sources and colliders. The field structure of a highly nonlinear plasma wake is potentially suitable for this purpose but has not been yet measured. Here we show that the longitudinal variation of the fields in a nonlinear plasma wakefield accelerator cavity produced by a relativistic electron bunch can be mapped using the bunch itself as a probe. We find that, for much of the cavity that is devoid of plasma electrons, the transverse force is constant longitudinally to within ±3% (r.m.s.). Moreover, comparison of experimental data and simulations has resulted in mapping of the longitudinal electric field of the unloaded wake up to 83 GV m(-1) to a similar degree of accuracy. These results bode well for high-gradient, high-efficiency acceleration of electron bunches while preserving their emittance in such a cavity.
authors.affiliation: Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Clayton
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|Department of Physics, University of Oslo, Oslo 0316, Norway.
authors.forename: E
authors.initials: E
authors.lastname: Adli
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: J
authors.initials: J
authors.lastname: Allen
authors.affiliation: Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA.|Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA.
authors.forename: W
authors.identifier: 0000-0003-3829-3526
authors.initials: W
authors.lastname: An
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: C I
authors.initials: CI
authors.lastname: Clarke
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.|LOA, ENSTA ParisTech, CNRS, Ecole Polytechnique, Université Paris-Saclay, Palaiseau 91762, France.
authors.forename: S
authors.identifier: 0000-0002-5015-0387
authors.initials: S
authors.lastname: Corde
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: J
authors.initials: J
authors.lastname: Frederico
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: S
authors.initials: S
authors.lastname: Gessner
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: S Z
authors.initials: SZ
authors.lastname: Green
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Hogan
authors.affiliation: Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA.
authors.forename: C
authors.initials: C
authors.lastname: Joshi
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: M
authors.initials: M
authors.lastname: Litos
authors.affiliation: Department of Engineering Physics, Tsinghua University, Beijing 100084, China.
authors.forename: W
authors.initials: W
authors.lastname: Lu
authors.affiliation: Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Marsh
authors.affiliation: Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA.|Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA.
authors.forename: W B
authors.initials: WB
authors.lastname: Mori
authors.affiliation: Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA.
authors.forename: N
authors.identifier: 0000-0003-2619-1303
authors.initials: N
authors.lastname: Vafaei-Najafabadi
authors.affiliation: Department of Electrical Engineering, University of California Los Angeles, Los Angeles, California 90095, USA.|Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, California 90095, USA.
authors.forename: X
authors.initials: X
authors.lastname: Xu
authors.affiliation: SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA.
authors.forename: V
authors.initials: V
authors.lastname: Yakimenko