Alcator C-Mod (in operation since 1993) and its predecessors, Alcator A (1975-1982) and Alcator C (1982-1988) have been built to explore the physics of plasmas in a compact, high field device. The word Alcator is an acronym derived from the Italian words Alto Campo Torus, meaning high field torus, and the magnetic fields produced in Alcator tokamaks are among the highest ever achieved in the world. Alcator's high confining fields let researchers experiment with plasmas hotter and denser than those in tokamaks of similar size. The Alcator C was the first device to produce the density (n) and confinement (tau) parameters of hot plasma (n.tau - the "Lawson criterion") necessary for a useful (equivalent deuterium-tritium) fusion reaction.

During its many years of operation, the Alcator C-Mod has been carrying out a number of innovative research techniques and technologies that are important for burning plasmas (ITER). Some of this research includes plasma boundary and surface physics, divertor physics, plasma confinement, plasma control, plasma disruptions and fast particle modes, radio-frequency (ion cyclotron and lower hybrid) heating and current drive, advanced tokamak studies, and accompanying diagnostics that kept the C-Mod program in the forefront of world fusion research. Alcator C-Mod also provides unparalleled hands-on experience for graduate students to conduct thesis research work and to learn how to operate and carry out experiments on a world-class tokamak.

The breadth and depth of the Alcator C-Mod research program and its contributions to ITER are clearly evident in the fourteen papers contained in FS&T special issue. John Rice is the guest editor for the issue and preface is written by Miklos Porkolab.

For further information on obtaining access to this issue or other tokamak special issues, contact Nermin Uckan (uckanna@ornl.gov) or visit the FS&T journal site at http://www.ans.org/pubs/journals/fst/