2026-09-18 九州大学
実験による磁化プラズマ生成とリコネクションの様子。 高出力レーザーで電離した炭素プラズマは自己生成された磁場とともに膨張し、中間面で磁気リコネクションが発生する。
＜関連情報＞
- https://www.kyushu-u.ac.jp/ja/researches/view/1575
- https://journals.aps.org/pre/abstract/10.1103/2b4s-5m1n
レーザーアブレーションプラズマにおけるビアマン電池駆動型磁気リコネクションの時間的変化の特性評価 Characterizing the temporal evolution of Biermann-battery-driven magnetic reconnection in laser-ablated plasmas
T. Morita, Y. Muramoto, S. Isayama, M. Edamoto, M. Hanano, R. Ishikawa, Y. Kanesada, K. Koba, H. Kondo et al.
Physical Review E Published: 8 September, 2026
DOI: https://doi.org/10.1103/2b4s-5m1n
Abstract
This paper presents an experimental investigation of magnetic reconnection between two laser-produced expanding plasmas, focusing on the quantitative evaluation of the reconnection rate and energy conversion under varying initial conditions. By changing the separation distance between the drive laser focal spots (1 mm and 2 mm), we systematically controlled the inflow parameters. The reconnection region was probed using a two-directional laser Thomson scattering (LTS) system, which simultaneously measured the local plasma parameters parallel to the outflows and along the current sheet. Based on our established method incorporating macroscopic energy and mass conservation laws to derive the upstream magnetic field directly from LTS spectra, we characterized the temporal evolution of the current sheet and the reconnection rate. The larger spot separation allows the plasma bubbles to expand for a substantially longer time before the formation of a reconnection current sheet, resulting in different upstream conditions. Nevertheless, both configurations yielded comparable upstream magnetic fields and reconnection rates. These results suggest that the reconnection rate is relatively insensitive to the global inflow conditions and is primarily controlled by the local physics of the reconnection layer once a current sheet is formed.
