Sep 15 – 21, 2019
Hotel Hermitage, La Biodola Bay, Isola d'Elba, Italy
Europe/Rome timezone

Control of electron injection in laser wakefield acceleration with external magnetic fields

Sep 18, 2019, 7:00 PM
Parking Area (Hotel Hermitage)

Parking Area

Hotel Hermitage

poster WG6 - Theory and simulations Cheese and Wine Poster Session 2


Zhengming Sheng (University of Strathclyde)


It is shown that external magnetic fields at tens of tesla can provide additional control of electron injection in laser wakefield acceleration (LWFA). In the first case, we consider ionization injection assisted by a transverse magnetic field. Both the electron trapping condition and the wakefield structure are changed significantly by the magnetic field such that injection occurs over a shorter distance and at an enhanced rate. Furthermore, beam loading is compensated for as a result of the trapezoidal-shaped longitudinal charge density profile of injected electrons. These lead to a reduction in the energy spread and an enhancement of both the charge and final peak energy of the electron beam.

In the second case, we consider density downramp injection assisted by a longitudinal magnetic field. The 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. This enables the start and end of electron injection to be independently controlled, allowing the generation of sub-femtosecond electron bunches with peak currents of a few kilo-Ampere.

Primary authors

Zhengming Sheng (University of Strathclyde) Dr Qian Zhao (Shanghai Jiao Tong University, China) Dr Suming Weng (Shanghai Jiao Tong University, China) Prof. Min Chen (Shanghai Jiao Tong University, China) Prof. Jie Zhang (Shanghai Jiao Tong University, China) Prof. Bernhard Hidding (University of Strathclyde, UK) Prof. Dino Jaroszynski (University of Strathclyde, UK) Dr Ralph Assmann (Deutsches Elektronen-Synchrotron DESY, Germany) Prof. Warren Mori (University of California, Los Angeles, USA)

Presentation materials