Coulomb implosion mechanism of negative ion acceleration in laser plasmas

Nakamura, Tatsufumi; Fukuda, Yuji; Yogo, Akifumi; Tampo, Motonobu; Kando, Masaki; Hayashi, Yukio; Kameshima, Takashi; Pirozhkov, A. S.; Esirkepov, T. Z.; Pikuz, T. A.*; Faenov, A. Y.; Daido, Hiroyuki; Bulanov, S. V.

In this study, we propose the Coulomb implosion mechanism of the negative ion acceleration in laser plasmas. When a cluster target is irradiated by an intense laser pulse and the ponderomotive pressure of the laser light blows away the electrons, the repelling force of an uncompensated electric charge of positive ions causes the cluster Coulomb explosion. In the case of a multi-species cluster with a relatively small number of the negative ions, the electric field formed by the positively charged component accelerates the negative ions inward. The negative ions leave the target, passing through the center or bouncing its vicinity. Theoretical description and present the results of the Particle-in-Cell simulation of the Coulomb explosion/implosion of a multi-species cluster are presented at the meeting.