Bolometer diagnostics on Alcator C-mod

Abstract

Bolometry is a diagnostic technique common to most tokamak fusion experiments. Bolometers are so widespread because they provide an important measure of the energy lost from confined plasmas as radiation, as well as being relatively simple and resilient in their construction. Here the bolometric diagnostics of the Alcator C-mod tokamak, their function, limitations, and the details of their calibration, operation, and maintenance are covered. In addition, the results of a variety of investigations into the behavior of C-mod plasmas as observed by bolometers are presented and discussed. The measurements dealt with are either measurements of total power radiated by the plasma or measurements of radial emissivity profiles. Measurements of the first kind are suitable for studying the effects of factors like net input power while measurements of the second kind are useful for studying the effects of factors like local temperature profiles and plasma composition.