@misc{oai:repo.qst.go.jp:00073356,
 author = {ビアワーゲ, アンドレアス and エシロケポフ, ティムル and コーガ, ジェームズ and ピロジコフ, アレキサンダー and 黄, 開 and 神門, 正城 and 桐山, 博光 and 相羽, 信行 and 松山, 顕之 and 篠原, 孝司 and 矢木, 雅敏 and Bierwage, Andreas and Timur, Esirkepov and Kevin Koga, James and Pirozhkov, Alexander and HUANG, KAI and Kando, Masaki and Kiriyama, Hiromitsu and Aiba, Nobuyuki and Matsuyama, Akinobu and Shinohara, Koji and Yagi, Masatoshi},
 month = {Nov},
 note = {Existing methods for diagnostics and control are still insufficient to deal with the various kinds of instabilities and collective dynamics that occur in magnetically confined fusion plasmas, which may impact the missions of the ITER and DEMO projects. Using small-scale laser experiments on J-KAREN-P, extensive numerical simulations on JFRS-1, and theoretical analyses, we are investigating whether short pulses (ps-fs) of a high power laser (TW-PW) may be used to address some of these issues. Based on the outcome of this feasibility study, we will make recommendations for applying accessible high-power laser technology in tokamaks for confinement control and plasma diagnostics.
    A laser pulse with relativistic intensity produces an electron density wake wave on the 10 ps scale. Extrapolations from experimental data (using similarity scaling) as well as 2D and 3D simulations for tokamak-relevant parameters (low density, strong external magnetic field) consistently indicate that the electron wake is sustained long enough to transform into a longer-lived ion density channel after a few 100 ps. The external magnetic field (~ 2 T) enhances the induced magnetic vortices (~ 5×) and reduces the induced electric field (~ 1/2×). Radiation emitted from the channel may be used for diagnostics.
    In the absence of thermal ion motion and collisions, the laser-induced channel is projected to survive for 100 ns. However. for typical tokamak ion temperatures (~ 3 keV), the channel will be mixed in the phase space of the gyrating ions within a few nanosecs (Landau damping). The further evolution of these phase space structures and possible echo-like recurrences of the channel in strongly magnetized plasmas are now under investigation. If sustained on the 20 ns scale, the channel may be reinforced by recycling the laser pulse. This would enhance its potential for affecting MHD-scale dynamics., 2nd QST International Symposium: “Frontier of Quantum Beam Science with High Power Lasers”},
 title = {Exploring high power laser effects on magnetically confined fusion plasmas},
 year = {2018}
}