Acceleration of Electrons in Plasma

This is brief review of acceleration of electrons in plasma wakefields driven by either intense laser pulses or particle beams following lectures at the 2019 CERN Accelerator School on plasma accelerators, held at Sesimbra, Portugal. The commonalities between drivers and their strength parameters and operating parameter regimes for current experiments in laser wakefield acceleration (LWFA) and beam driven plasma wakefield acceleration (PWFA) are summarized. Energy limitations are introduced, including the dephasing and depletion lengths for lasers, and the transformer ratio for beam driven plasmas. The concept of the wake Hamiltonian is introduced and the resulting particle orbits are identified in phase space, which illustrates how the peak energy and energy spread of accelerated electrons are determined.