Ablation of nonlinear-force driven plasma blocks for fast igniter application

Abstract

Interaction of TW-ps laser with plasma results in a skin layer mechanism for nonlinear (ponderomotive) force driven two dimensional plasma blocks (pistons) if a very high contrast ratio is provided for suppression of relativistic self-focusing. This Skin layer acceleration (SLA) [1] results in space charge neutral plasma blocks with ion current densities larger than 10 10 Amp/cm 2 [1-3]. Using Ions in the MeV range results in 1000 times higher proton or DT current densities [3] than the proton fast igniter [4] is using and may result in better conditions of this fast ignitor scheme. Using ballistic focusing of the generated plasma blocks and a short time thermal expansion of these blocks for increasing their thickness while keeping the high ion current densities, results in conditions favourable for this option of fast ignition of a fusion target. Some details of the interaction processes are still to be analysed but the solutions studies to date are most encouraging.