title: Turn on the super-elastic collision nature of coronal mass ejections through low approaching speed.
abstract: It has been proved from the observations and numerical simulations that the collision between solar coronal mass ejections (CMEs), the largest plasmoids in the heliosphere, could be super-elastic. This finding suggests that the CMEs' magnetic energy and thermal energy could be converted into kinetic energy through a more efficient way. However CME collisions are not always super-elastic, which means that this distinct property of plasmoids is probably excited conditionally. As the first attempt, we carry out a series of three-dimensional numerical experiments, and establish a diagram showing the dependence of the collision nature on the CME speed and k-number, the ratio of the CME's kinetic energy to the CME's total energy. It is found that the super-elastic nature of CMEs appears at the relatively low approaching speed, and most of the previous case studies are in agreement with this diagram. Our study firmly advances the understanding of the super-elastic property of plasmoids, and does give us new clues to deeply understand why and how the magnetic energy and/or thermal energy of the colliding plasmoids can be converted into kinetic energy in such an efficient way.
authors.affiliation: SIGMA Weather Group, State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Shen
authors.affiliation: CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.|Synergetic Innovation Center of Quantum Information &Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China.
authors.forename: Yuming
authors.initials: Y
authors.lastname: Wang
authors.affiliation: CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei, Anhui 230026, China.|Collaborative Innovation Center of Astronautical Science and Technology, Hefei 230026, China.
authors.forename: Chenglong
authors.initials: C
authors.lastname: Shen
authors.affiliation: SIGMA Weather Group, State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190, China.
authors.forename: Xueshang
authors.initials: X
authors.lastname: Feng