Reverse Ion Acceleration Via Laser-Matter Interaction

Summary form only given. Ion acceleration via laser plasma interaction is an area of research that attracted a lot of attention over the past few years. The general experimental setup is a laser pulse hitting an over- or underdense foil target. Several mechanisms responsible for the ion acceleration have been identified, including sheath normal acceleration or shock acceleration at the foil interior. For underdense or slightly overdense targets, the ion acceleration is mainly in forward direction, parallel to the initial laser propagation. For some applications it might be of interest to accelerate ions in the backward direction. One concept to accomplish this is to send the laser pulse through an underdense, low-Z coating before it hits the overdense, high-Z target. The target is spherically shaped and acts as a focusing mirror. The incident laser intensity is chosen low enough that the ions are not accelerated via the ponderomotive force. We are currently investigating this concept using the fully kinetic plasma simulation code VORPAL and present results of these simulations