Diagnostics for Lab and Astrophysical Plasmas

Abstract

To monitor effects of vacuum conditioning, three radiation diagnostics are being built: a Helium–Neon (HeNe) heterodyne interferometer, a Bolometer, and a Hydrogen-alpha (Hα) detector. The interferometer will measure the line-average refractive index of the plasma, enabling us to obtain the line average density. The bolometer is a soft X-ray/UV detector (similar to those used on the Sustained Spheromak Physics Experiment (McLean et al. in Rev. Sci. Instruments 72(1):556–561, 2001) and the High-Beta Tokamak Experiment (Xiao and Navratil. in Rev. Sci. Instrument 67(9):3334–3335, 1996) and is used to directly measure the radiation loss from photons. The Hα detector will detect the amount of Hα being emitted by the plasma as a function of time, thus gauging the neutral density. These same concepts are also applied to astrophysical plasmas, with slightly different approaches. A brief overlap between diagnostics/detectors for laboratory and astrophysical plasmas is discussed.