Measurements of Electron Feature in Laser-Produced Collisionless Plasmas Using Thomson Scattering
Nima Bolouki1*, C. W. Peng1, C. H. Chen1, T. Y. Huang1, N. Khasanah1, T. Moritaka1,2, Y. Hara3, H. Shimogawara3, Y. Sakawa3, Y. Sato4, K. Tomita4, K. Uchino4, S. Matsukiyo4, Y. Shoji5, S. Tomita5, S. Tomiya5, R. Yamazaki5, M. Koenig6,7, Y. Kuramitsu1
1Department of Physics, National Central University, Taoyuan, Taiwan
2National Institute for Fusion Science, National Institutes of Natural Sciences, Toki, Japan
3Institute of Laser Engineering, Osaka University, Suita, Osaka, Japan
4Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, Fukuoka, Japan
5Department of Physics and Mathematics, Gakuin University, Aoyama, Japan
6Laboratoire pour I'Utilisationdes Lasers Intenses, CNRS-CEA-Universite Paris VI, EcolePolytechnique, Palaiseau, France
7Institute for Academic Initiatives, Osaka University, Suita, Osaka, Japan
* presenting author:Nima Bolouki,
Laser Thomson scattering as a diagnostics system which provide high spatial and temporal resolutions is the only non-intrusive method for measuring local fundamental quantities of laser-produced collisionless plasmas in laboratory since such plasmas have nanosecond life time and millimeter size. It should be noted that astrophysical collisionless shock experiments have the ability to provide us the local and global information. Collective Thomson scattering, in which the scattering from electron moving collectively, has been performed to magnetic reconnection experiments with Gekko XII HIPER laser facility. Since the signal intensity of electron term is much smaller than that of ion term, it is overwhelmed by strong background plasma emission. In order to solve this problem, stimulated Brillouin scattering has been employed to compress the probe laser to 500 picosecond. As a result, the electron feature has been successfully detected at 45 ns after the main laser irradiation. The spatial profile of electron density ne, electron temperature Te, and drift velocity have been estimated in the ablation plasma. The gradient of ne and Te have been shown. The measured ne are in good agreement with interferometry results.

Keywords: Laser-Produced Collisionless Plasmas, Astrophysical Collisionless Shockwaves , Laboratory Astrophysics , Plasma Diagnostics , Laser Thomson Scattering Diagnostics