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

What we know about plasma rotation

CONFINEMENT TYPE

POLOIDAL ROTATION

TOROIDAL ROTATION

Low Well described by Neoclassical

Theory

Anomalous

High Anomalous Anomalous

Central toroidal plasma rotation in different tokamaks

Machine Vtor(cm/s) R (cm) a (cm) B(T) Ip(kA)

LT-3 +5.10⁵ 40 10 1 33

PLT -1,5.106 132 40 3 600

JFT-2 -1,3.106 90 25 1,8 230

TorusII +1,6.106 30 20 0,67 250

PDX ≤3.10⁵ 140 45 2,5 600

TM-4 -7.10⁵ 53 8,5 1,5 25

ISX ≈ 0 92 26 1,8 220

JET ≤ -2,4.10⁶ 296 125 2,7 2500

DIII-D -2,5.10⁶ 160 56 2,2 2000

TCA ± 2,5.10⁶ 61 18 1,5 100

TCABR -2.10⁶ 61 18 1,1 100

Diagnostics for plasma rotation measurements

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

New technique

462 463 464 465 466 4670.0

0.2

0.4

0.6

0.8

1.0

Inte

nsity

wavelength [nm]

2-

2

0 1

1+

A1 A

2

slit1 slit2

)(2

1 fS

Sf

PMT

PMT

Gaussian profile of spectral line

dQnndS qpIePMT 1

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

462 463 464 465 466 4670.0

0.2

0.4

0.6

0.8

1.0

Inte

nsi

ty

wavelength [nm]

2-

2

0 1

1+

A1 A

2

slit1 slit2

4340 4345 4350 4355 4360 4365 4370 4375 43800.0

0.5

1.0

1.5

2.0

2.5

3.0

Inte

nsi

ty o

f si

gn

al [

V]

wavelength [A]

instrument function of THR1000 monochromator

axial slitwidth = 80 m

lateral slitwidth = 80 m

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

0.00 0.05 0.10 0.15 0.20 0.25 0.300

1

2

3

4

5

6

0.00 0.05 0.10 0.15 0.20 0.25 0.30-0.15-0.10-0.050.000.050.100.15

Ra

tio

o

f s

ig

na

ls

Doppler Shift [A]

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

30 40 50 60 70 80 90 100 110 120 130 140-2.00x106

-1.75x106

-1.50x106

-1.25x106

-1.00x106

-7.50x105

-5.00x105

-2.50x105

0.00

polo

idal

vel

ocity

[cm

/s]

time [ms]

shot 22260

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).

30 40 50 60 70 80 90 100 110 120 130-1.0x106

-8.0x105

-6.0x105

-4.0x105

-2.0x105

0.0

2.0x105

po

loid

al v

elo

city

[cm

/s]

time [ms]

Shot 22258

Preliminary results

30 40 50 60 70 80 90 100 110 120 130 140-2.00x106

-1.75x106

-1.50x106

-1.25x106

-1.00x106

-7.50x105

-5.00x105

-2.50x105

0.00

2.50x105

polo

idal

vel

ocity

[cm

/s]

time [ms]

shot 22261

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).

30 40 50 60 70 80 90 100 110 120 130 140-1.50x106

-1.25x106

-1.00x106

-7.50x105

-5.00x105

-2.50x105

0.00

2.50x105

po

loid

al v

elo

city

[cm

/s]

time [ms]

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.