Towards attosecond high-energy electron bunches: controlling self-injection in laser wakefield accelerators through plasma density modulation

Research output: Contribution to journalArticle

Self-injection in a laser-plasma wakefield accelerator (LWFA) is usually achieved by increasing the laser intensity until the threshold for injection is exceeded. Alternatively, the velocity of the bubble accelerating structure can be controlled using plasma density ramps, reducing the electron velocity required for injection. We present a model describing self-injection in the short bunch regime for arbitrary changes in the plasma density. We derive the threshold condition for injection due to a plasma density gradient, which is confirmed using particle-in-cell (PIC) simulations that demonstrate injection of sub-femtosecond bunches. It is shown that the bunch charge, bunch length and separation of bunches in a bunch train can be controlled by tailoring the plasma density profile.
Original languageEnglish
Article number044801
Number of pages6
JournalPhys. Rev. Lett.
Volume119
DOIs
StatePublished - 26 Jul 2017

    Research areas

  • self-injection, controlled injection, LWFA, laser wakefield acceleration, attosecond electron bunches

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