Many-electron stripping in collisions between atoms and heavy ions

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 Clsup(z+) ions at 50 MeV (2 <= Z <= 15). The predicted cross sections for removing all 10 electrons from Ne have peak values 0.005 πa02 for effective charges 10 <= Z <= 55; the cross sections for direct production of Ne7+ (1s2s2p 4P) may be as large as 0.1 πa02. The dependence of these cross sections on energy is complicated but their variation with Z at a fixed energy is usually rather gentle. (author)