Grant: Discovery Grants Program - Individual

There are two areas of research proposed:(1) the experimental investigation of collisions between electrons and atoms or molecules in the presence of an intense laser; and (2) the measurement of cross-sections for the excitation of highly-charged atomic ions by the impact of electrons.(1) The proposed area of collision physics involves the collision of electrons and atoms or molecules but with the added complexity of a third body, a particle of light, the photon, entering the collision event.  The photon, supplied by a high-powered laser system, introduces new parameters into the process which may interfere with the collision in a number of intersting ways.  For example, new processes may occur which are not possible through the energy of the electron or photon alone, but may become possible through the use of the enrgy of both the electron and photon together.  The study of such elementary processes is fundamental to our understanding of many aspects of astrophysics and plasma physics and has been an active area of research, both theoretically and experimentally, for many years.(2) In certain regions of plasmas in nuclear fusion reactors(tokamaks) and also in stars, low energy electron collisions with atomic ions play a key role.  The probability of excitation and ionization of the atomic ions by electrons needs to be known.  The vast majority of the large number of these processes occuring in the different regions of tokamaks have been, and will continue to be, provided by theoretical calculations, but there continues to be a need for a selection of experimental data to be used as tests of the theoretical methods.  These are extremely difficult experiments which are being pursued by an international team at Oak Ridge National Labs, TN using the source for highly ionised atoms that is situated there.  I am an active member of this successful team.