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. [1] [2]
Proton rotation has been measured using spectral line emission from excited fast neutrals created from inner core plasma protons via charge exchange transfer reactions. [3]
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. [4]
A vacuum ultraviolet spectrometer is used for performing spectral surveys and specialized plasma studies. [5] [6]
The chord-integrated emissions of spectral lines are monitored by using a spectral system with time and space scanning capabilities and relative calibration over the entire UV-visible spectral range. This system has been used to study the line ratio of lines of different ionization stages of carbon C5+ 5290 Å and C4+ 2271 Å for plasma diagnostic purposes. [7]
References
- ↑ A. Baciero et al, A multi-channel spectroscopic system for measuring impurity ion temperatures and poloidal rotation velocities in TJ-II, Rev. Sci. Instrum. 72 (2001) 971
- ↑ B. Zurro et al, Comparison of Impurity Poloidal Rotation in ECRH and NBI Discharges of the TJ-II HELIAC, Fusion Science and Technology 50, 3 (2006) 419-427
- ↑ B. Zurro et al, Investigation of proton rotation measurements using hydrogen line wings in the TJ-II stellarator, Rev. Sci. Instrum. 74 (2003) 2056
- ↑ D. Rapisarda et al, Novel passive spectroscopy system for absolutely referenced plasma rotation measurements in clean plasmas, Rev. Sci. Instrum. 77 (2006) 033506
- ↑ K.J. McCarthy et al, A toroidal focusing mirror based vacuum ultraviolet diagnostic for TJ-II, Rev. Sci. Instrum. 70 (1999) 312
- ↑ K.J. McCarthy et al, A Study of Spectral Lines in Plasmas Heated by Neutral Beam Injection in the TJ-II Stellarator, AIP Conf. Proc. 1058 (2008) 219-221
- ↑ B. Zurro et al, An experimental system for spectral line ratio measurements in the TJ-II stellarator, Rev. Sci. Instrum. 79 (2008) 10F540