[P-EM33_1AM1] プラズマ宇宙：観測・実験の計画・手法，装置開発，プラズマ計測

[PEM33-04] 大型レーザーを用いた無衝突ワイベル衝撃波の生成

*坂和 洋一¹、森田 太智¹、蔵満 康浩²、加藤 恒彦³、森高 外征雄¹、佐野 孝好¹、富田 健太郎⁴、松清 修一⁴、大西 直文⁵、水田 晃⁶、Woolsey N⁷、Gregori G⁸、Koenig M⁹、Spitkovsky A¹⁰、Huntington C¹¹、Kugland N L¹¹、Ross J S¹¹、Park H-S¹¹、Remington B¹¹、高部 英明¹ (1.阪大レーザー研、2.国立中央大学　台湾、3.広島大、4.九州大、5.東北大、6.理化学研究所、7.ヨーク大　英国、8.オックスフォード大　英国、9.LULI フランス、10.プリンストン大 米国、11.ローレンツリバモア研　米国)

キーワード：無衝突衝撃波, ワイベル不安定性, 大型レーザー実験

Collisionless shocks are considered to be sources of high-energy particles or cosmic rays, and occur when a coulomb mean-free-path is longer than the shock-front thickness. In such plasmas wave-particle interactions and collective effects play an essential role in the shock formation. In addition to local observations of spaces plasmas by spacecraft and global emission measurements of astrophysical plasmas, a laboratory experiment can be an alternative approach to study the formation of collisionless shocks. In this paper, we investigate the formation of Weibel-instability mediated collisionless shocks in counter-streaming plasmas produced by large-scale laser systems. Kato and Takabe investigated the collisionless Weibel shock in two-dimensional PIC simulation using the injection method [1]. A scaling-law derived in simulation revealed that high-density (electron density 〜10²⁰ cm^-3), high-flow velocity (〜1000 km/s) plasmas are required to produce the collisionless Weibel shock. In order to achieve these plasma parameters, a MJ-class high-power laser system or the word largest laser, the NIF laser (LLNL, USA), is required. Before starting the NIF experiment, we conducted OMEGA laser (LLE, USA) experiment and measured plasma parameters such as electron and ion temperatures, electron density, and flow velocity of counter-streaming plasmas using collective Thomson scattering, and current filaments produced by the Weibel instability using proton-radiography.[1] T. N. Kato and H. Takabe, The Astophys. J. Lett. 681, L93 (2008).