ideas for overseas contributions to cmso piero martin consorzio rfx associazione euratom-enea sulla...
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Ideas for “overseas” Ideas for “overseas” contributions to CMSOcontributions to CMSO
Piero MartinPiero Martin
Consorzio RFX Consorzio RFX Associazione Euratom-ENEA sulla fusioneAssociazione Euratom-ENEA sulla fusioneAnd Physics Dept., Univ. of Padova, ItalyAnd Physics Dept., Univ. of Padova, Italy
CMSO General Meeting CMSO General Meeting Madison, WI – Aug. 6-8, 2004Madison, WI – Aug. 6-8, 2004
With contributions from RFX, MST, EXTRAP T2R and TPE-RX groupsWith contributions from RFX, MST, EXTRAP T2R and TPE-RX groups
The new RFX deviceThe new RFX device
Main new components:Main new components:
1.1. 192 saddle coils, covering the whole plasma boundary, each 192 saddle coils, covering the whole plasma boundary, each independently powered and feedback controlledindependently powered and feedback controlled
2.2. a smoother and thinner shella smoother and thinner shell
3.3. the first wall with higher power handling capabilitiesthe first wall with higher power handling capabilities
4.4. an in-vessel system of magnetic and electrostatic probesan in-vessel system of magnetic and electrostatic probes
5.5. the toroidal field power supplythe toroidal field power supply
R R //aa = 2.0 / 0.46 (m) - = 2.0 / 0.46 (m) - II up to 2 MA up to 2 MA
Overview of the magnetic boundaryOverview of the magnetic boundary
- 4 coils in the poloidal direction: 90° spaced– 48 coils in the toroidal direction: 7.5° spaced
shellshellvessevessell
Active Active saddle saddle coilscoils
Saddle coil performanceSaddle coil performance
each independently powered24 kAt: 400 A x 60 turns
Wide spectrum of Fourier Wide spectrum of Fourier components can be components can be produced:produced:
•m=1,2•n ≤ 24•DC < f < 100 Hz
Significant amplitude available. For example: edge br for (1,8) mode:
• 20 mT@10 Hz• 1.3 mT @100 Hz
Magnetic probeMagnetic probe
•97 Electrostatic (Langmuir) probes•139 Magnetic pick up probes •8 Calorimetric probes
Langmuir probeLangmuir probe
Integrated System of the Internal Sensors Integrated System of the Internal Sensors (ISIS)(ISIS)
RFX and CMSO activitiesRFX and CMSO activities
Active feedback controlActive feedback control of magnetic of magnetic turbulence in a laboratory plasma device with turbulence in a laboratory plasma device with FULL COVERAGEFULL COVERAGE of the plasma surface. of the plasma surface.
Selective depression/excitation of selected MHD Selective depression/excitation of selected MHD instabilitiesinstabilities
Dynamo studiesDynamo studies Resistive Wall Modes controlResistive Wall Modes control Magnetic turbulence controlMagnetic turbulence control ……………………
… … together with strong plasma diagnostic together with strong plasma diagnostic capabilitiescapabilities!!
The Single Helicity (SH) dynamoThe Single Helicity (SH) dynamo
a theoretically predicted state with a unique a theoretically predicted state with a unique m m = 1 saturated resistive = 1 saturated resistive kink (kink (a pure helix wound on a torusa pure helix wound on a torus), ),
Stationary Stationary LAMINARLAMINAR dynamo mechanism with good helical flux surfaces dynamo mechanism with good helical flux surfaces
MAC-302MAC-302
Escande, Martin et al., PRL 85 Escande, Martin et al., PRL 85 (2000)(2000)
Dynamo electric field in QSHDynamo electric field in QSH
Dynamo in QSH becomes more concentrated in Dynamo in QSH becomes more concentrated in one mode than in standard MH plasmas!one mode than in standard MH plasmas!
)~~( bv
Piovesan, Craig, Marrelli, Martin, submitted to PRL
QSH coherent structureQSH coherent structure
Remember we can apply with the saddle coils up to ~20 mT
on a single m=1 mode
10-9
10-8
10-7
10-6
10-5
0.0001
0.001
0.5 1 1.5 2 2.5
eps42wf3_4/f5_10
Wr( 0, 1)Wr( 0, 2)Wr( 1, 1)Wr( 1, 2)Wr( 1, 3)Wr( 1, 4)Wr( 1, 5)Wr( 1, -1)Wr( 1, -2)Wr( 1, -3)Wr( 1, -4)Wr( 1, -5)Wr( 1, -6)Wr( 1, -7)Wr( 1, -8)Wr( 1, -9)Wr( 1,-10)Wr( 1,-11)Wr( 1,-12)Wr( 1,-13)
Time
Numerical studies on active control: successful drive and sustainment of m=1 n=7 SH state starting from MH
conditions
•Low dissipation Low dissipation conditionsconditions
•Thin shellThin shell
•Simoultaneous Simoultaneous active control of active control of RWMs !RWMs !
Paccagnella, MHD workshop 2002
Preliminary experiments in the EXTRAP T2R Preliminary experiments in the EXTRAP T2R RFPRFP
RFX equipment tested in the EU EXTRAP T2R device at KTH in StockholmRFX equipment tested in the EU EXTRAP T2R device at KTH in Stockholm QSH spectra excited in a high aspect ratio device!QSH spectra excited in a high aspect ratio device! More experiments underwayMore experiments underway
Test particle transport studies: Test particle transport studies: magnetic stochasticity vs. ordermagnetic stochasticity vs. order
SHSH QSHQSH MHMH
Numerical simulation predicts better confinement in SHNumerical simulation predicts better confinement in SH
With the ORBIT code a set of test particles is deposited in the With the ORBIT code a set of test particles is deposited in the plasma core in plasma core in MH/QSH/SHMH/QSH/SH and followed in their outward motion. and followed in their outward motion.
Particle loss time estimated; confinement Particle loss time estimated; confinement SH > QSH > MHSH > QSH > MH
Poloidal anglePoloidal angle Predebon et al, submitted to PRL
Upgraded soft x-ray tomography for Upgraded soft x-ray tomography for MSTMST
Two more fans added: total 4Two more fans added: total 4
Franz et al., RSI 2004
Imaging of individual small islands in the Imaging of individual small islands in the plasma coreplasma core
SXR imageSXR image
Numerical reconstruction of Numerical reconstruction of magnetic field linesmagnetic field lines
Franz et al., PR:L 2004