Tokamak experiments have made dramatic progress over the past two decades, and today plasma parameters are nearing the values needed for a fusion reactor. (See the article by J. Geoffrey Cordey, Robert J. Goldston and Ronald R. Parker on page 22.) In November 1991 the first deuterium‐tritium experiments in the Joint European Torus in Abingdon, England, generated a peak fusion power of almost 2 megawatts and a total energy release of 2 megajoules in a 2‐second pulse. Concomitant progress has been made in understanding the basic physics of tokamakplasmas; this was made possible by major developments in plasma science, nonlinear theory, plasma diagnostic capabilities and supercomputer calculations.
With the macroscopic behavior of tokamak plasmas now reasonably well understood, a major challenge is to develop the physics of plasma turbulence and of the particle and heat fluxes it induces.