Search for a Spectroscopic Signature of Periodic Fields Found in Magnetic Fusion Devices

Spectroscopic measurement campaigns are underway on the large helical device (LHD) and Heliotron J fusion devices in Japan. These campaigns aim to detect on the line shapes of hydrogen Balmer and Paschen lines a spectroscopic signature of periodic electric fields generated by gyrotrons. We present computer simulation calculations of hydrogen line shapes under plasma and periodic electric fields conditions expected along the lines of sight. Our calculations predict the emergence of replicas of the Zeeman‐Stark profile located at multiples of the oscillation frequency. We also discuss the primary factors influencing the visibility of these spectral features.