G.T. Hoang, C. Bourdelle, B. Pégourié, J. F. Artaud, J.Bucalossi, F. Clairet,

TTF, Madison, Apr 2003 1G.T. Hoang

TORE SUPRAAssociationEuratom-Cea

G.T. Hoang, C. Bourdelle, B. Pégourié, J. F. Artaud, J.Bucalossi, F. Clairet,C. Fenzi-Bonizec, X. Garbet, C. Gil, R. Guirlet, F. Imbeaux, J. Lasalle, T. Loarer,

C. Lowry, B. Schunke, J. M. Travère, E. Tsitrone, and the Tore Supra Team.(to appear in PRL)

Evident Anomalous Inward Particle Pinch in Full Non-Inductive Plasmas Driven by

Lower Hybrid Waves on Tore Supra



Ip = 0.52 MA, gas DBootstrap 15%

LH power 3 MWLine density 2.5x1019m-2

Te(0) = 4.8 keVTi(0) = 1.3 keVp = 0.5N = 0.4

Stationary Zeff 2 MHD stable

01234

LH power (MW)

line density (x1019m-2)

Ip (MA)Vloop(V)

-0.20

0.20.4

01234

Te (keV)

r/a=0r/a=0.2

00.5

11.5

2

0 1 2 3 4Time (minute)

Zeff

MHD

#30414

Ti(0)

STEADY-STATE FULLY LHCD



0

0.5

1

1.5

2

2.5

3

0 0.2 0.4 0.6 0.8 1Normalized radius

n e (x

1019

m-3

)

Reflectometry

Interferometry

29 profiles from 3s - 60s

#30428

PEAKED DENSITY PROFILEIN FULLY LHCD PLASMAS

0

1

2

3

0 10 20 30 40 50 60Time (s)

n

(x10

19/m

4 ) @ r/a = 0.5

0

1

2

3

4

LH power (MW)

line density ( x1019m-2)

Vloop (V)

#30428

= - D ne + V. ne

Ware pinch = 0 Particle Source 0? or Anomalous Pinch?




0

1

2

3

4n e

dur

ing

LH

CD

nor

mal

ized

to

ne

in

Ohm

ic

8 channels of Thomson scattering, from 10s - 250s

#30414

Main Change @ r / a > 0.6, due to Recycling Source, when LHCD is switched on.

RESILIENT DENSITY PROFILEIN THE GRADIENT REGION


TORE SUPRAAssociationEuratom-Cea ABSENCE OF TOROIDAL

ELECTRIC FIELD

E Null Over the Whole Plasma Volume(from current diffusion simulation)

Ip = 0.5 MA, B = 4T, ne(0) = 2.5 1019 m-3

Te(0) ~ 4.8 keV; Ti(0) ~ 1.3 keV

r/a = 0.2 / 0.4 / 0.6

Time (minute)

0

0.2

0.4

0.6

0.8

1

0 1 2 3 4

E

(x10

-2 V

/m

)

#30414



Neoclassical pinch (Vneo) from NCLASS including all neoclassical effects

Cannot Be Invoked to Explain Peaked Density Profile

-10123456


Vne

o (x

10-2

m /

s)

Full LHCD @ t=170s

OH @ t=4.8s

WARE PINCH VANISHESACROSS THE WHOLE PLASMA



Negligible Particle Source In the Core Region (r / a < 0.6)

Less Than 1% of Recycling and Gas Puff Sources Inside r/a = 0.7

0 0.2 0.4 0.6 0.8 1 1.20

0.5

1

1.5

Normalized radius

Par

ticl

e so

urce

(x10

21 P

art.

/m

3 /s

)

3D neutral code EIRENE

PEAKED PROFILELINKED TO TRANSPORT PROPERTIES

From C6+ and O8+

0

0.5

1

1.5

2

2.5

0

1

2

3

4

0 0.2 0.4 0.6 0.8 1Ele

ctro

n de

nsit

y (x

1019

m-3

)

Zeff

Normalized radius

Zeff

Total

Negligible Impurity Source

C and O dominant



RATIO V / D CLOSE TO 1m-1

IN THE GRADIENT REGION

No Central Source V / D = 1 / Ln

r (m)

1 /

Ln

(m-1

)

0.01

0.1

1

10

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

= - D ne + V. ne



Two Orders of Magnitude Above Vneo, during LHCD phase

0.0001

0.001

0.01

0.1

1

10


V(m/s)

D(m2/s)

Vneo (m/s)

D = Dohmic (slightly underestimated)

Overestimated Vneo with Zeff = 6 gives 3.10-3 m.s-1

NEED AN INWARD PINCHMUCH HIGHER THAN NEOCLASSICAL VALUE



Same Simulated Profile may be Obtained with V Vneo, But D Lower Than Collisionnal Value Required

Taking into account the parallel particle sink in SOL Outer part of the discharge accurately described

0

0.5

1

1.5

2

2.5

3

0 0.2 0.4 0.6 0.8 1 1.2Normalized radius

n e (

x101

9 m-3

)

Particle source (a.u)

__ : Simulation__ : Reflect & InterferometryO : Reflectometry

#30428

PROFILE WELL REPRODUCEDBY 1D SIMULATION


TORE SUPRAAssociationEuratom-Cea n/n NEITHER PROPORTIONAL

TO q/q NOR T/T



ISICHENKO’s FORMULA FITS BETTER

n(r)n(0)

1 1R

(120

r 4

3s)

PRL 74, 1995worked quite well on 35 TFTR shots

Normalized radius

Nor

mal

ized

pro

file

T /q

1/q

ne

Isichenko



SUMMARY

•Density Profile Remains Peaked for More Than 3Minutes in Fully LHCD Discharges.

• Peaked Density Profile Can Only Be Explained by aParticle Pinch Velocity Two Orders of Magnitude Abovethe Neoclassical Pinch.

• Radial Profile in Agreement with Isichenko’s Formula.

G.T. Hoang, C. Bourdelle, B. Pégourié, J. F. Artaud, J.Bucalossi, F. Clairet,

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