Continuum x-ray emission from the AlcatorAtokamak

X rays from 1 to 25 keV emitted by the Alcator A device have been collected with a Si(Li) detector and pulse-height-analysis system. Under normal operating conditions, spectra are thermal, indicating clean (Zeff~1), Maxwellian distributions. Temperature profiles are provided. When vdvₜₕ0.03, the x-ray spectra become nonthermal, reflective of non-Maxwellian distributions. The observed nonthermal behavior increases with minor radius and poloidal symmetry, is correlated with poor energy confinement, and cannot be accounted for by classical electric-field-driven perturbation theory. Radial electron diffusion is discussed.