1. School of Space Science and Physics, Shandong University, Weihai 264209, China
2. Shandong Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Science, Shandong University, Weihai264209, China
3. School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China
4. State Key Laboratory of Crystal Materials, Institute of Crystal Materials, Shandong University, Jinan 250100, China