An ultrahigh-bandwidth Phase Contrast Imaging system for fusion plasmas

Abstract

A novel Phase Contrast Imaging system that uses probing light in the near infrared region has been developed to image electron density fluctuations in fusion plasmas. As compared to standard systems operating in the mid infra-red region, the spectral response of the system is extended in wave-number and frequency response by 7 and 100 times, respectively. The internal structure of turbulence and radio-frequency waves is therefore accessible across an unprecedented wavelength and frequency range, extending into the electron gyro-radius scale and the GHz frequency region.