Scaling laws for direct laser acceleration in a radiation-reaction dominated regime

Abstract

We study electron acceleration within a sub-critical plasma channel irradiated by an ultra-intense laser pulse ( a _0 > 100 or I > 10 ^22 W cm ^−2 ). In this regime, radiation reaction significantly alters the electron dynamics. This has an effect not only on the maximum attainable electron energy but also on the phase-matching process between betatron motion and electron oscillations in the laser field. Our study encompasses analytical description, test-particle calculations and two-dimensional particle-in-cell simulations. We show single-stage electron acceleration to multi-GeV energies within a 0.5 mm-long channel and provide guidelines how to obtain energies beyond 10 GeV using optimal initial configurations. We present the required conditions in a form of explicit analytical scaling laws that can be applied to plan the future electron acceleration experiments.

Keywords

• ultra-intense laser
• particle acceleration
• radiation reaction
• direct laser acceleration
• laser–plasma interaction