Electron Scale Magnetic Reconnection in Laser Produced Plasmas
Y. Kuramitsu1*, T. Moritaka1,2, Y. Sakawa3, T. Morita3,4, T. Sano3, M. Koenig5,6, C. D. Gregory7, N. Woolsey8, K. Tomita9, H. Takabe10, Y. L. Liu1, S. H. Chen1, S. Matsukiyo11, M. Hoshino12
1Department of Physics, National Central University, Taoyuan, Taiwan
2Department of Helical Plasma Research, National Institute for Fusion Science, Toki, Japan
3Institute of Laser Engineering, Osaka University, Suita, Japan
4Department of Advanced Energy Engineering Science, Kyushu University, Kasuga, Japan
5LULI, Ecole Polytechnique, Palaiseau, France
6Institute for Academic Initiatives, Osaka University, Suita, Japan
7Rutherford Appleton Laboratory, Didcot, UK
8Department of Physics, University of York, York, UK
9Interdisciplinary Graduate School of Engneering and Science, Kyushu University, Kasuga, Japan
10Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
11Department of Earth System Science and Technology, Kyushu University, Kasuga, Japan
12Department of Earth and Planetary Science, University of Tokyo, Hongo, Japan
* presenting author:Yasuhiro Kuramitsu, email:yasu@ncu.edu.tw
We experimentally investigate electron scale magnetic reconnections in laser produced plasmas under the influence of a weak-external magnetic field perpendicular to a plasma propagation axis. The magnetic field is strong enough to magnetize the electrons but not the ions; the magnetic field is not directly coupled with ions. In the presence of such a weak magnetic field, the plasma collimation was observed by interferometry. Since no collimation was observed without the magnetic field, the presence of the magnetic field, and thus, the electron dynamics is essential to the plasma collimation. The distorted magnetic field due to the plasma dynamic pressure is locally anti-parallel, i.e., magnetic reconnection is possible. By applying the additional external pressure with an ambient plasma, we observed the cusp structure and the Alfvénic outflows, these are the essential aspects of magnetic reconnections.

Keywords: plasma, laser, magnetic reconnection, particle acceleration