Instability-free ion acceleration by two laser pulsesM.L. Zhou, S. Zhao, H.Y. Wang, C. Lin, H.Y. Lu, Y.R. Lu, T. Tajima, X.T. He, C.E. Chen, Y.Q. Gu and X.Q. YanEur. Phys. J. Special Topics, 223 6 (2014) 1031-1035DOI: https://doi.org/10.1140/epjst/e2014-02153-7