RFXmod

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RFX-mod
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Period of operation Dec. 20, 2004 - Sept. 23,
2005

• Days shots
• 66 days
• 930 plasma pulses
• Program objectives
• Characterize reference performance
• Test new experiment features and flexibility
• Begin MHD active control program

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outline

• Reference passive performance
• m0 rotation control
• OPCD
• OFCD
• QSH
• SSCD
• RFT
• Active MHD control

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Reference performance
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Reference performance
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Locking position hystogram
Almost 50 of the discharges appear to lock close
to one of the two existing poloidal gaps
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Driven LM rotation by m0 perturbation
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Driven locked mode flipping
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feedback control on m0 modes
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OPCD experiments
Electron and Ion temperature increase is induced
during the co-dynamo phase. The trigger is
provided by the reduction in the amplitude of the
fluctuations in the toroidal magnetic field.
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OFCD test at 150 Hz 16687 (ref.) vs 16698
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QSH
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Self-similar current decay experiments
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Self-similar current decay
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RFT Tokamak?screw pinch/ULQ ?.RFP
q1.2
q2
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Virtual shell
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Plasma reproducibility increases with active
control
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Virtual shell Bt perturbations
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Non-axisymmetric shift
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br_edge m1
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Edge radial field
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Electron temperature
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Ion temperature
Ti from Doppler broadening of O VII 1623Å line
(radially the measurement corresponds to a mean
value of r/a 0.4) Te from double filter
Ti
Te
17092, with virtual shell
Ti Te
17082, without virtual shell
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Density profiles with (Blue 17077) and w/o
(Black 17082) virtual shell
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2
3
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Vloop
17089
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Heat diffusivity estimates
17079 - 17085 with virtual shell
17082 w/o virtual shell
35 ms
60 ms
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RWM growth
17280 Experimental measurement
Cylindrical Linear theory (experimental
equilibrium)
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RWM control studies in RFX-mod

• 17287 virtual shell, all modes.
• 17301 selective virtual shell, free evolution
  of m1, n-3, -4, -5, -6. n-6 most unstable.
• 17304 same as 17301, but with active control on
  m1, n-6 from t150 ms on.

n-6 control off n-6
control on
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Rapid progress
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accomplishments

• Demonstrated experiment flexibility
• Reproduced basic passive performance
• Obtained good active equilibrium control
• Reproduced LM driven rotation by m0
• Tested many operating conditions (SSCD, RFT..)
• Started MHD active control experiments
• Achieved successful initial virtual shell
  operation
• Measured significant reduction of magnetic
  perturbations
• Obtained 600 kA long pulses (5 shell times)
  with1/3 Vs
• Obtained up to 30 increase in energy confinement
  time
• Started successful RWM control experiments

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future

• Mode control (RWM and TM)
• Virtual shell optimization
• VS m0 control, ramping, OPCD .
• High density
• High current
• Plasma parameters optimization
• Study new operating conditions
• Open to suggestions and collaborations

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MANY THANKS TO THE RFX TEAM !!!
P. Agostinetti, M. Agostini, A. Alfier, V.
Antoni, L. Apolloni, F. Auriemma, W. Baker, F.
Basso, M. Bigi, P. Bettini, T. Bolzonella, D.
Bonfiglio, F. Bonomo, A. Buffa, A. Canton, S.
Cappello, L. Carraro R. Cavazzana, M. Cavinato,
G. Chitarin, A. Cravotta, S. Dal Bello, M. Dalla
Palma, A. De Lorenzi, L. De Pasqual, D. Desideri,
D.F. Escande, P. Fiorentin, P. Franz, G. Gadani,
E. Gaio, L. Garzotti, E. Gazza, L. Giudicotti, F.
Gnesotto, M. Gobbin, L. Grando, S.C. Guo, P.
Innocente, R. Lorenzini, A. Luchetta, G.
Malesani, G. Manduchi, G. Marchiori, D. Marcuzzi,
L. Marrelli, P. Martin, E. Martines, S. Martini,
A. Masiello, F. Milani, M. Moresco, A. Murari, P.
Nielsen, S. Ortolani, , R. Paccagnella, R.
Pasqualotto, S. Peruzzo, R. Piovan, P. Piovesan,
N. Pomaro, M.E. Puiatti, G. Rostagni, F. Sattin,
P. Scarin, V. Schmidt, G. Serianni, G. Sias, P.
Sonato, E. Spada, A. Soppelsa, G. Spizzo, M.
Spolaore, C. Taccon, C. Taliercio, D. Terranova,
P. Testoni, V. Toigo, M. Valisa, N. Vianello, P.
Zaccaria, P. Zanca, B. Zaniol, L. Zanotto, E.
Zilli, G. Zollino, M. Zuin