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Temporal evolution of plasma rotation measurement in tokamaks using an optical monochromator and two photomultipliers as detector. Severo J. H. F . E-mail jhsevero@if.usp.br Institute of Physics, University of São Paulo, Rua do Matão, s/n, 05508-900 SP, Brasil.
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Temporal evolution of plasma rotation measurement in tokamaks using an optical monochromator and two photomultipliers as detector Severo J. H. F. E-mail jhsevero@if.usp.br Institute of Physics, University of São Paulo, Rua do Matão, s/n, 05508-900 SP, Brasil
Contents • Motivation • Diagnostics for plasma rotation measurements • New technique • TCABR parameters • Preliminary results • Conclusions
Charge-exchange recombination spectroscopy D0(nD)+AZ+ → D++A(Z-1)+(n)* σCX= σCX (│V-Vb│) Expensive Small time resolution Multichannel diode array detector Expensive Small time resolution Diagnostics for plasma rotation measurements
New technique Gaussian profile of spectral line
Experimental set-up for temporal evolution of poloidal plasma rotation measurements Experimental set-up used for temporal evolution of plasma poloidal rotation measurements.
Spectral profiles Gaussian profile of spectral line. A semi-transparent mirror is used to produce a small shift in wavelength and the photomultipliers integrate different portions of the profile. Instrumental function of the THR1000 monochromator (slitwidth 2200X80μm) obtained scanning the HgI (4358,4A) spectral line.
Doppler shift calibration Dependence between ratio of signals with Doppler shift.
TCABR plasma parameters • Plasma Major Radius 61 cm • Plasma Minor Radius 18 cm • Toroidal Magnetic Field 1.1 T • Plasma Current ≈ 100 kA • Plasma Discharge Duration ≈ 120 ms • Electron Density (1.0 - 4.0).1019 m-3 • Electron Temperature ≈ 600 eV • Ion Temperature ≈ 200 eV
Photograph TCABR
Preliminary results Temporal evolution of the TCABR poloidal rotation measured at r = 16 cm (shot 22258). Temporal evolution of the TCABR poloidal rotation measured at r = 16 cm (shot 22260).
Preliminary results Temporal evolution of the TCABR poloidal rotation measured at r = 16 cm (shot 22261). Temporal evolution of the TCABR poloidal rotation measured at r = 16 cm (shot 22262).
Conclusions • A new method was proposed for measurements of temporal evolution of plasma rotation in tokamaks. • The direction of poloidal velocity in the TCABR coincides with the diamagnetic electron drift. • These results show good agreement, within experimental uncertainty, with previous results [1-2]. • Reference • [1] Severo J. H. F. at al - 2003 Nuclear Fusion 43 1047. • [2] Severo J. H. F. at al - 2007 Review of Scientific Instruments 78 043509.