Doppler Reflectometer System in the Stellarator TJ-II Articles uri icon

publication date

  • July 2009

start page

  • 73502


  • 7


  • 80

International Standard Serial Number (ISSN)

  • 0034-6748

Electronic International Standard Serial Number (EISSN)

  • 1089-7623


  • A Doppler reflectometer system has recently been installed in the stellarator TJ-II. The system is optimized for the Q-band (33&-50 GHz) and the high-curvature plasmas produced in TJ-II. The launch angle of the microwave beam can be controlled by a steerable mirror to obtain angles between ±20° enabling the measurement of perpendicular wave numbers in the range of 3&-15 cm−1. The available angular range allows for comparisons between positive and negative values and additionally for calibration of the system. Localization and k⊥-estimation is done via the three-dimensional ray/beam-tracing code TRUBA. First measured spectra and radial profiles of the perpendicular velocity of plasma density fluctuations are presented.