Quasi-Monoenergetic Electron Beam Generation from Nanothickness Solid Foils Irradiated by Circular-Polarization Laser Pulses

Ultrashort 10²²–10²⁴ W/cm² laser pulses will offer the possibility of producing monoenergetic electron beams in the GeV–TeV level in the future. A laser-electron acceleration scheme is proposed by the interaction between a thin solid foil and an ultra-intense laser pulse for a₀≥800σ₀, where a₀ is the normalized laser field and σ₀ is the normalized plasma surface density. The energy of the electrons as a function of time can be described by a simple model which indicates that an exponential relationship exists between the energy and the normalized time τ. A quasi-monoenergetic high density electron beam with 1.3 GeV energy and a 2.2% energy spread has been predicted for a₀=223.5 by particle-in-cell simulations. Characteristics of the ultra-high density electron layer formed in the early period of the acceleration are discussed.