Institute of Modern Physics;
Chinese Academy of Sciences;
Lanzhou 730000;
China;
University of Chinese Academy of Sciences;
Beijing 100049;
China;
Hefei National Laboratory for Physical Sciences at Micro-scale;
Department of Modern Physics;
University of Science and Technology of China;
Hefei 230026;
China;
storage; ring; electron; cooler; highly; charged; ions; radiative; recombination; enhancement;