Moment-equation approach to impurity transport in tokamaks

The purpose of this report is to overview neoclassical impurity transport through a fluid theory description, and experiments relevant to the topic. Three theoretical forms for particle transport are discussed here. The distinctions among these are mainly historical, as all can be included within the same framework, although the resulting transport effects differ greatly. The three, in order of historical development, are classical, Pfirsch-Schlueter, which introduced geometric effects, and neoclassical, which included long mean free path effects