1. Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, Institute of Space Sciences; Shandong University; Weihai China
2. Physics Department; University of New Brunswick; Fredericton New Brunswick Canada
3. Department of Physics; University of Oslo; Oslo Norway
4. Bradley Department of Electrical and Computer Engineering; Virginia Tech; Blacksburg VA USA
5. Department of Physics and Astronomy; University of Leicester; Leicester UK