Yonghong Liu, Haiyi Sun, Jingjing Ju, Ye Tian, Yafeng Bai, Cheng Wang, Tiejun Wang, Jiansheng Liu, See Leang Chin, Ruxin Li. Vortices formation induced by femtosecond laser filamentation in a cloud chamber filled with air and helium[J]. Chinese Optics Letters, 2016, 14(3): 031401