Benchmark calculations of electron-lithium scattering for beam diagnostics on tokamaks

Beams of light elements, such as lithium, are important diagnostics in controlled plasma fusion devices. Consequently there is a great need for accurate atomic data for excitation and ionization processes in neutral lithium and its ions. In recent years, much progress has been made in calculating accurate cross sections for electron-impact excitation and ionization processes using non-perturbative techniques. These methods can now provide benchmark accuracy for the electron-impact excitation and ionization of simple atomic systems. For example, for the electron-impact ionization of hydrogen, all the non-perturbative methods yield total cross section results that are in excellent agreement with experimental measurements. These techniques have recently been extended to calculate excitation and ionization cross sections for neutral lithium and its ions. Excellent agreement is found between the three non-perturbative methods employed, and in some cases, large disagreements are found with previous existing experimental measurements