Highly charged ion

Highly charged ions (HCI) are ions in very high charge states due to the loss of many or most of their bound electrons by energetic collisions or high-energy photon absorption. Examples are 13-fold ionized iron, Fe¹³⁺ or Fe (XIV) in spectroscopic notation, found in the Sun's corona, or naked uranium, U⁹²⁺, bare all bound electrons, which requires very high energy for its production. HCI are found in stellar coronae, in active galactic nuclei, in supernova remnants, and in accretion disks. Most of the visible matter found in the universe consists of highly charged ions. High temperature plasmas used for nuclear fusion energy research also contain HCI generated by the plasma-wall interaction (see Tokamak). In the laboratory, HCI are investigated by means of heavy ion particle accelerators and electron beam ion traps.

References

• H. F. Beyer, H.-J. Kluge, V. P. Shevelko, in: X-ray Radiation of Highly Charged Ions, Springer Series on Atoms and Plasmas, Springer Verlag, Berlin-Heidelberg 1997

• "Highly Charged Ions", J. D. Gillaspy, J. Phys. B: At. Mol. Opt. Phys. 34, R93-R130 (2001).