Trace impurity transport code

FLOREX is a code which solves the coupled transport equations of all the charge states of a single impurity atomic species in a fixed plasma background. The impurity ions are taken to be present in a trace amount so that their self-collisions are neglected. Consequently, the coupling is due entirely to ionization and recombination. This report describes the equations, the numerical method, and an example of its use in the impurity flow reversal experiment