Sub-femtosecond electron bunches in laser wakefield acceleration via injection suppression with a magnetic field

Q. Zhao, S. M. Weng, M. Chen, M. Zeng, B. Hidding, D. A. Jaroszynski, R. Assmann, Z. M. Sheng

Research output: Contribution to journalArticle

Abstract

It is shown that electron injection into a laser-driven plasma bubble can be manipulated by applying an external magnetic field in the presence of a plasma density gradient. The down-ramp of the density-tailored plasma locally reduces the plasma wave phase velocity, which triggers injection. The longitudinal magnetic field dynamically induces an expanding hole in the electron density distribution at the rear of the wake bubble, which reduces the peak electron velocity in its vicinity. Electron injection is suppressed when the electron velocity drops below the phase velocity, which depends on the size of the density hole. This enables the start and end of electron injection to be independently controlled, which allows generation of sub-femtosecond electron bunches with peak currents of a few kilo-Ampere, for an applied magnetic field of ∼ 10 Tesla.
LanguageEnglish
Number of pages12
JournalPlasma Physics and Controlled Fusion
Publication statusAccepted/In press - 16 May 2019

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Electron injection
Plasma density
Phase velocity
retarding
injection
Magnetic fields
Electrons
Lasers
magnetic fields
lasers
Plasma waves
Electronic density of states
electrons
phase velocity
plasma density
plasma bubbles
Plasmas
plasma waves
ramps
wakes

Keywords

  • electron injection
  • laser-driven plasma bubble
  • external magnetic field
  • sub-femtosecond electron bunches

Cite this

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title = "Sub-femtosecond electron bunches in laser wakefield acceleration via injection suppression with a magnetic field",
abstract = "It is shown that electron injection into a laser-driven plasma bubble can be manipulated by applying an external magnetic field in the presence of a plasma density gradient. The down-ramp of the density-tailored plasma locally reduces the plasma wave phase velocity, which triggers injection. The longitudinal magnetic field dynamically induces an expanding hole in the electron density distribution at the rear of the wake bubble, which reduces the peak electron velocity in its vicinity. Electron injection is suppressed when the electron velocity drops below the phase velocity, which depends on the size of the density hole. This enables the start and end of electron injection to be independently controlled, which allows generation of sub-femtosecond electron bunches with peak currents of a few kilo-Ampere, for an applied magnetic field of ∼ 10 Tesla.",
keywords = "electron injection, laser-driven plasma bubble, external magnetic field, sub-femtosecond electron bunches",
author = "Q. Zhao and Weng, {S. M.} and M. Chen and M. Zeng and B. Hidding and Jaroszynski, {D. A.} and R. Assmann and Sheng, {Z. M.}",
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T1 - Sub-femtosecond electron bunches in laser wakefield acceleration via injection suppression with a magnetic field

AU - Zhao, Q.

AU - Weng, S. M.

AU - Chen, M.

AU - Zeng, M.

AU - Hidding, B.

AU - Jaroszynski, D. A.

AU - Assmann, R.

AU - Sheng, Z. M.

PY - 2019/5/16

Y1 - 2019/5/16

N2 - It is shown that electron injection into a laser-driven plasma bubble can be manipulated by applying an external magnetic field in the presence of a plasma density gradient. The down-ramp of the density-tailored plasma locally reduces the plasma wave phase velocity, which triggers injection. The longitudinal magnetic field dynamically induces an expanding hole in the electron density distribution at the rear of the wake bubble, which reduces the peak electron velocity in its vicinity. Electron injection is suppressed when the electron velocity drops below the phase velocity, which depends on the size of the density hole. This enables the start and end of electron injection to be independently controlled, which allows generation of sub-femtosecond electron bunches with peak currents of a few kilo-Ampere, for an applied magnetic field of ∼ 10 Tesla.

AB - It is shown that electron injection into a laser-driven plasma bubble can be manipulated by applying an external magnetic field in the presence of a plasma density gradient. The down-ramp of the density-tailored plasma locally reduces the plasma wave phase velocity, which triggers injection. The longitudinal magnetic field dynamically induces an expanding hole in the electron density distribution at the rear of the wake bubble, which reduces the peak electron velocity in its vicinity. Electron injection is suppressed when the electron velocity drops below the phase velocity, which depends on the size of the density hole. This enables the start and end of electron injection to be independently controlled, which allows generation of sub-femtosecond electron bunches with peak currents of a few kilo-Ampere, for an applied magnetic field of ∼ 10 Tesla.

KW - electron injection

KW - laser-driven plasma bubble

KW - external magnetic field

KW - sub-femtosecond electron bunches

UR - https://iopscience.iop.org/journal/0741-3335

M3 - Article

JO - Plasma Physics and Controlled Fusion

T2 - Plasma Physics and Controlled Fusion

JF - Plasma Physics and Controlled Fusion

SN - 0741-3335

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