Abstract
Recent experiments suggest that a highly stripped ion can remove up to 10 electrons in a single collision with a neutral atom or molecule. It is shown that this process can take place through the coherent superposition of the heavy ion's electric field at different times, in a way analogous to multiphoton ionisation by intense radiation fields. For relatively fast ions, a simple theory is developed and results are presented for a variety of cases. The theory is in reasonable agreement with measured cross sections for 1s-vacancy production in Ne by ClZ+ ions at 50 MeV (2<or=Z<or=15).