Abstract
The key issue to achieve controlled fusion is to confine a very high temperature plasma for a sufficiently long time.
However, plasma confinement is limited by thermal transport processes, and therefore, one of the main goals of plasma
physics research is to understand transport. Coulomb collisions provide the most basic, and natural transport mechanism
in a plasma. However, transport calculations based only on coUisional effects (i.e., classical and neoclassical
transport theories) tend to underestimate the transport levels experimentally observed in magnetically confined fusion
plasmas. It is believed that plasma instabilities and turbulence play a critical role in the observed enhanced transport.
The study of turbulence-driven transport, also known as anomalous transport, has therefore attracted a lot of attention.
Although significant progress has been made in the classical, neoclassical, and anomalous theories of transport, there
are important open problems likely to play a role in the design and operation of present and future fusion devices
including ITER. A common feature of these problems is that they seem to defy our intuition rooted in the concept of
diffusive transport.
