Super-ponderomotive electron acceleration in blowout plasma heated by multi-picosecond relativistic intensity laser pulse

Abstract

The dependence of the mean kinetic energy of laser-accelerated electrons on the laser intensity, so-called ponderomotive scaling, was derived theoretically with consideration of the motion of a single electron in oscillating laser fields. This scaling explains well the experimental results obtained with high-intensity pulses and durations shorter than a picosecond; however, this scaling is no longer applicable to the multi-picosecond (multi-ps) facility experiments. Here, we experimentally clarified the generation of the super-ponderomotive-relativistic electrons (SP-REs) through multi-ps relativistic laser-plasma interactions using prepulse-free LFEX laser pulses that were realized using a plasma mirror (PM). The SP-REs are produced with direct laser acceleration assisted by the self-generated quasi-static electric field and with loop-injected direct acceleration by the self- generated quasi-static magnetic field, which grow in a blowout plasma heated by a multi-ps laser pulse. Finally, we theoretically derive the threshold pulse duration to boost the acceleration of REs, which provides an important insight into the determination of laser pulse duration at kilojoule- petawatt laser facilities.

References in corpus (5)

• Optical Properties of Relativistic Plasma Mirrors
• Beyond the ponderomotive limit: direct laser acceleration of relativistic electrons in sub-critical plasmas
• Scaling the Yield of Laser-Driven Electron-Positron Jets to Laboratory Astrophysical Applications
• Generation of 'Super-Ponderomotive' Electrons due to a non-Wakefield interaction between a Laser Pulse and a Longitudinal Electric Field
• On The Origin of Super-Hot Electrons from Intense Laser Interactions with Solid Targets having Moderate Scale Length Preformed Plasmas