Generation of attosecond x-ray pulses with a multicycle two-color enhanced self-amplified spontaneous emission scheme

摘要: Generation of attosecond x-ray pulses is attracting much attention within the free-electron laser (FEL) user community. Several schemes using extremely short to manipulate electron bunches have been proposed. In this paper, we extend two-color ESASE scheme proposed by Zholents et al. long optical cycle regime a second detuned and tapered undulator. Both lasers can be about ten-optical-cycles long, with frequency from first optimize contrast between central side current spikes. A undulator mitigates degradation effect longitudinal space charge (LSC) force in suppresses FEL gain all peaks. Simulations LCLS parameters show single spike {approx} 110 attoseconds produced. The also coherently control number spikes length radiation pulse.