TJ-II:Spectroscopy

TJ-II disposes of an eight-channel, high-resolution, spectroscopic diagnostic system. This system is currently being used to measure impurity ion temperature and poloidal rotation using passive emission spectroscopy. The principal features of the diagnostic include independent focusing of its channels, high sensitivity for performing Doppler measurements in low-density ECR-heated plasmas, as well as a flexible and fast in-house-developed software program for performing integrated data reduction and analysis.

Another method for measuring absolutely calibrated rotation velocities consists of simultaneously recording the emission lines from the plasma and from a calibration lamp by means of a double fiber-fiber guide.