NSTX-U Supported by Physical Characteristics of Neoclassical - - PowerPoint PPT Presentation

Physical Characteristics of Neoclassical Toroidal Viscosity in Tokamaks for Rotation Control and the Evaluation of Plasma Response

• S. A. Sabbagh1, R.E. Bell2, T.E. Evans3, N.

Ferraro3, I.R. Goumiri4, Y.M. Jeon5, W.H. Ko5, Y.S. Park1, K.C. Shaing6, Y. Sun7, J.W. Berkery1, D.A. Gates2, S.P. Gerhardt2, S.H. Hahn5, C.W. Rowley4

1Department of Applied Physics, Columbia University, New York, NY 2Princeton Plasma Physics Laboratory, Princeton, NJ 3General Atomics, San Diego, CA 4Princeton University, Princeton, NJ 5National Fusion Research Institute, Daejeon, Republic of Korea 6National Cheng Kung University, Tainan, Taiwan 7ASIPP, Hefei Anhui, China

NSTX-U

Supported by

Culham Sci Ctr York U Chubu U Fukui U Hiroshima U Hyogo U Kyoto U Kyushu U Kyushu Tokai U NIFS Niigata U U Tokyo JAEA

Inst for Nucl Res, Kiev

Ioffe Inst TRINITI Chonbuk Natl U NFRI KAIST POSTECH Seoul Natl U ASIPP CIEMAT FOM Inst DIFFER ENEA, Frascati CEA, Cadarache IPP, Jülich IPP, Garching ASCR, Czech Rep

25th IAEA Fusion Energy Conference October 14th, 2014

• St. Petersburg,

Russian Federation

V1.9m

Coll of Wm & Mary Columbia U CompX General Atomics FIU INL Johns Hopkins U LANL LLNL Lodestar MIT Lehigh U Nova Photonics ORNL PPPL Princeton U Purdue U SNL Think Tank, Inc. UC Davis UC Irvine UCLA UCSD U Colorado U Illinois U Maryland U Rochester U Tennessee U Tulsa U Washington U Wisconsin X Science LLC

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

The physical characteristics of NTV investigated in tokamaks for rotation control and the evaluation of plasma response

 Motivation

 Low magnitude (dB/B0 ~ O(10-3)) 3D magnetic fields are used favorably

used in tokamaks (e.g. ELM suppression, MHD mode control)

 3D fields of this magnitude can produce neoclassical toroidal viscosity

(NTV), which can:

• Alter plasma rotation
• Significantly reduce fusion gain, Q, by increased alpha particle transport

(dB/B0 ~ O(10-4))

 Therefore, it is important to understand NTV in tokamaks, backed by

accurate (~O(1)) quantitative modeling

 Outline

 NTV physical characteristics  NTV comparison of theory to experiment  NTV experiments and assessment of plasma response  Application of NTV to plasma rotation control for NSTX-U

2

K.C. Shaing, et al., Nucl. Fusion 54 (2014) 033012 K.C. Shaing, et al., IAEA FEC 2014 Paper TH/P1-11

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Neoclassical Toroidal Viscosity (NTV) can be studied through the application of 3D fields in tokamaks

 Theory: NTV strength varies with

plasma collisionality n, dB2, rotation

3

K.C. Shaing, M.S. Chu, C.T. Hsu, et al., PPCF 54 (2012) 124033

NSTX 3D coils

  n

   n   I p R B R B

NC i i i t t t

e

) ( 1 1

2 3 2 / 3 1 2 ) / 1 (

     

  

plasma rotation

Ti

5/2

K.C. Shaing, et al., PPCF 51 (2009) 035004

KSTAR 3D coils NTV force in “1/n” collisionality regime

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

NTV physical characteristics are generally favorable for rotation control

 Non-resonant NTV characteristics (e.g. in

NSTX and KSTAR)

 3D field configurations with dominant toroidal

mode number n > 1 can alter the plasma rotation profile, , without mode locking

 Experimentally, NTV torque is radially

extended, with a relatively smooth profile

 NTV changes continuously as the applied 3D

field is increased

 TNTV is not simply an integrated torque

applied at the plasma boundary, but a radial profile – e.g.  shear can be changed

 These aspects are generally favorable for

rotation control; give potential mode control

 Questions remain

 e.g. Is there hysteresis when  is altered by

NTV?

4

 alteration by n = 2 applied field configuration in NSTX

10 20 30 0.9

t(s) 0.575 0.585 0.595 0.605 0.615 0.625

1.0 1.1 1.2 1.3 1.4 1.5

R(m)

• uter region

braking saturates at this time

/2 (kHz)

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25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

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KSTAR experiments show essentially no hysteresis in steady-state  profile vs. applied 3D field strength

 Experiment run to produce

various steady-state  with different 3D field evolution

 The steady-state rotation

profile reached is generally independent of the starting point of 

 depends just on the applied

3D field current level

 important for rotation control

 Absence of hysteresis further

confirmed in very recent experiments with 6 steps in 3D field current

5

KSTAR non-resonant (“n = 2”) NTV experiments Plasma rotation profiles 3D field current (kA/t) 3D field current stepped up / down

0 kA/t 2.7 kA/t 3.8 kA/t 3.3 kA/t

 (krad/s)

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

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Neoclassical Toroidal Viscosity varies as dB2, and Ti

2.27 in

KSTAR experiments, expected by theory

6

Y.S Park, et al., IAEA FEC 2014: EX/P8-05 (Fri. PM)

n = 2 field current vs. time Plasma rotation profile vs. time

 NTV torque TNTV expected to scale

as dB2 and Ti

2.5 in the “1/n regime”

Best fit:  dB2 Best fit:  Ti

2.27

 steady-state reached each dB step

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25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

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3D field perturbation experiments conducted to measure the TNTV profile in NSTX

 High normalized beta plasma targets typically chosen

 Typically near or above n = 1 no-wall limit (for higher Ti)

 Apply or otherwise change 3D field on a timescale

significantly faster than the momentum diffusion time, tm

 Analysis before/after 3D field application isolates TNTV in the

momentum diffusion equation; -dL/dt = TNTV

 dL/dt measured experimentally and compared to theoretically

computed TNTV on this timescale

 dL/dt profile can change significantly on timescales > tm, (diffuses

radially, broadens, leads to significant error compared to TNTV)

 Focus on non-resonant applied 3D field configurations

 To avoid driving MHD modes  Resonant fields (e.g. n = 1) are more strongly screened by plasma

7

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Theoretical NTV torque density profiles, TNTV are computed for NSTX using theory applicable to all collisionality regimes

8

• 1.5
• 1
• 0.5

0.5 1 1.5

• 1.5
• 1
• 0.5

0.5 1 1.5

• 0.4
• 0.2

0.2 0.4

Non-axisymmetric coils fully modelled in 3D

 NTV analysis of NSTX – data interfaced

to NTVTOK

 Use Shaing’s “connected NTV model”,

covers all n, superbanana plateau regimes

 Full 3D coil specification and dB spectrum,

ion and electron components computed, no aspect ratio assumptions

(K.C. Shaing, Sabbagh, Chu, NF 50 (2010) 025022) (Y. Sun, Liang, Shaing, et al., NF 51 (2011) 053015) x(m) y(m) z(m)

   

B b B / B B d     

3D field definition

plasma displacement

 General considerations



In tokamaks,  not typically measured, can lead to large error



“Fully-penetrated field constraint” used to define 

• Singularities avoided by standard

finite island width assumption



For NSTX, | | ~ 0.3 cm << 0.5ri, therefore, ion banana width- averaging is used for ion channel

• Can explain why strong resonant

peaks in NTV profile are not

• bserved in experiment

 

2D

B b   

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Measured NTV torque density profiles quantitatively compare well to computed TNTV using fully-penetrated 3D field

9

n = 3 coil configuration n = 2 coil configuration

 TNTV (theory) scaled to match peak value of measured -dL/dt

 Scale factor ((dL/dt)/TNTV) = 1.7 and 0.6 (for cases shown above) – O(1) agreement  O(1) agreement using “fully-penetrated 3D field” indicates that plasma response is not

strongly amplified from this “vacuum field assumption” (TNTV ~ dB2)

Experimental

• dL/dt

yN

Experimental

• dL/dt

NTVTOK

yN

NSTX NSTX

NTVTOK

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Plasma response from fully-penetrated 3D field used in NTV experimental analysis matches M3D-C1 single fluid model

Surface-averaged dB from fully penetrated model vs. M3D-C1 single fluid model

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5 10 15 20 25 30 35 40 0.0 0.5 1.0 Flux surf avg |deltaB| (G) SQRT(Psi_norm) M3D-C1 Penetrated Field (NTVTOK)

(n = 3 configuration) Strong TNTV region core edge Flux surface-avg <dB> (G)

N

y

 NTV experimental data is a

strong quantitative constraint

• n plasma response of dB

 Because the measured NTV

scales as TNTV  dB2,

 Level of agreement varies

along the profile

 Good agreement between

NTVTOK / M3D-C1 single fluid models in strong NTV region

 M3D-C1 core <dB> larger than

NTVTOK

• Core mode in M3D-C1

 M3D-C1 edge <dB> smaller

• Experimental TNTV too small in

this region to constraint dB

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

200 400 600 800 1000 1200 1400 1600 1800 2000 1 2 3 4 5 6 7

Beam Power

Non-resonant NTV and NBI used as actuators in state-space rotation feedback controller designed for NSTX-U

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3D coil current and NBI power (actuators) t (s) t (s)

3D Coil Current (kA) feedback

• n

feedback

• n

0.5 0.6 0.7 0.8 0.5 0.6 0.7 0.8 2 1

NBI power (MW)

7 1 6 5 4 3 2

yN

NBI, NTV torque density (N/m2) Plasma rotation (rad/s)

NTV torque 6 8 10 104 desired 

t1 tend

4 2 NBI torque 0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.2 0.4 0.6 0.8 1.0

Rotation evolution and NBI and NTV torque profiles

• I. Goumiri (PU), S.A. Sabbagh (Columbia U.), D.A. Gates, S.P. Gerhardt (PPPL)

 

1 2 2 i i i i NBI NTV i i

V V n m R n m R T T t



  r r r r  r



                         

 

 Momentum force balance –  decomposed into Bessel function states  NTV torque:

 

 

 

2 K1 K2 e,i e,i NTV coil

T K f g B n I T d r       

(non-linear) (max.)

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

0.4 0.5 0.6 0.7 0.8 0.9 800 1000 1200 1400 1600 1800 2000 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3 4 5 6 7 Beam Power

When Ti is included in NTV rotation controller model, 3D field current and NBI power can compensate for Ti variations

12

t (s) t (s) 3D coil current and NBI power (actuators)

yN

NBI, NTV torque density (N/m2) Plasma rotation (rad/s)

NTV torque 104 desired 

t1

NBI torque

 NTV torque profile model for feedback

dependent on ion temperature

 

 

 

2 K1 K2 e,i NTV coil i

T K f g n T B I d r       

Rotation evolution and NBI and NTV torque profiles K1 = 0, K2 = 2.5

0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 200 400 600 800 1000 1200 1400 1600 1800

3D Coil Current (kA)

0.5 0.7 0.9 1.0 0.8 1.2 1.4 1.6 1.8 2.0 0.5 0.7 0.9

Ti (keV)

0.6 1.2 1.8 0.0 t (s) 0.5 0.7 0.9 0.8 0.6 0.4

NBI power (MW)

7 1 6 5 4 3 2 6 8 4 2 10 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.5 1.0 1.5 2.0 2.5

t1 t3 t2

(max.)

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Physical characteristics of NTV are investigated in tokamaks for rotation control and the evaluation of plasma response

 Experiments on NSTX and KSTAR show that non-resonant NTV torque

TNTV from applied 3D field is a radially extended, relatively smooth profile

 Analysis of KSTAR shows TNTV  (dB3D)2; TNTV  Ti

2.27; no hysteresis on

the rotation profile when altered by non-resonant NTV (key for control)

 3D field perturbation experiments in NSTX using both n = 2 and n = 3

field configurations measure the TNTV profile

 The measured TNTV profile quantitatively compares well between

experiment and Shaing’s “connected NTV theory”

 Non-resonant TNTV profile in NSTX is quantitatively consistent with “fully-

penetrated field” assumption of plasma response

 Surface-averaged 3D field profile from M3D-C1 single fluid model

consistent with field used for quantitative NTV agreement in experiment

 Rotation controller using NTV and NBI designed/tested for NSTX-U

13

K.C. Shaing, et al., NF 50 (2010) 025022)

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Extra slides for poster

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NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

200 400 600 800 1000 1200 1400 1600 1800 2000 1 2 3 4 5 6 7

Beam Power

Non-resonant NTV and NBI used as actuators in state-space rotation feedback controller designed for NSTX-U

15

3D coil current and NBI power (actuators) t (s) t (s)

3D Coil Current (kA) feedback

• n

feedback

• n

0.5 0.6 0.7 0.8 0.5 0.6 0.7 0.8 2 1

NBI power (MW)

7 1 6 5 4 3 2

1 1 2 2

t1 .0 0Τ t2 .6 8Τ t3 1 .9 9Τ t4 4 .7 8Τ

.0 .2 .4 .6 .8 1 .0

yN

NBI, NTV torque density (N/m2) Plasma rotation (rad/s)

NTV torque 6 8 10 104 desired 

t1 t4

4 2 NBI torque

t1 = 0.00t t2 = 0.68t t3 = 1.99t t4 = 4.78t

0.0 0.5 1.0 1.5 2.0 2.5 0.0 0.2 0.4 0.6 0.8 1.0

Rotation evolution and NBI and NTV torque profiles

• I. Goumiri (PU), S.A. Sabbagh (Columbia U.), D.A. Gates, S.P. Gerhardt (PPPL)

 

1 2 2 i i i i NBI NTV i i

V V n m R n m R T T t



  r r r r  r



                         

 

 Momentum force balance –  decomposed into Bessel function states  NTV torque:

 

 

 

2 K1 K2 e,i e,i NTV coil

T K f g B n I T d r       

(non-linear)

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

1 1 2 2

t1 0.59s t2 0.69s t3 0.79s

0.0 0.2 0.4 0.6 0.8 1.0 000 000 000 000 000

0.4 0.5 0.6 0.7 0.8 0.9 800 1000 1200 1400 1600 1800 2000 0.4 0.5 0.6 0.7 0.8 0.9 1 2 3 4 5 6 7 Beam Power

When Ti is included in NTV rotation controller model, 3D field current and NBI power can compensate for Ti variations

16

t (s) t (s) 3D coil current and NBI power (actuators)

yN

NBI, NTV torque density (N/m2) Plasma rotation (rad/s)

NTV torque 104 desired 

t1 t3

NBI torque

t1 = 0.59s t2 = 0.69s t3 = 0.79s

 NTV torque profile model for feedback

dependent on ion temperature

 

 

 

2 K1 K2 e,i NTV coil i

T K f g n T B I d r       

Rotation evolution and NBI and NTV torque profiles K1 = 0, K2 = 2.5

0.4 0.45 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 200 400 600 800 1000 1200 1400 1600 1800

3D Coil Current (kA)

0.5 0.7 0.9 1.0 0.8 1.2 1.4 1.6 1.8 2.0 0.5 0.7 0.9

Ti (keV)

0.6 1.2 1.8 0.0 t (s) 0.5 0.7 0.9 0.8 0.6 0.4

NBI power (MW)

7 1 6 5 4 3 2

t2 t1 t3 t2 t1 t2 t3

6 8 4 2 10 0.0 0.2 0.4 0.6 0.8 1.0 0.0 0.5 1.0 1.5 2.0 2.5

t1 t3 t2

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Measured NTV torque density profiles quantitatively compare well to computed TNTV using fully-penetrated 3D field

17

 TNTV (theory) scaled to match peak value of measured -dL/dt

 Scale factor ((dL/dt)/TNTV) = 1.7 and 0.6 (for cases shown above) – O(1) agreement  O(1) agreement using “fully-penetrated 3D field” indicates that plasma response is not

strongly amplified from this “vaccum field assumption” (TNTV ~ dB2)

Experimental

• dL/dt

NTVTOK

yN

Experimental

• dL/dt

yN

NSTX NSTX

NTVTOK

n = 3 coil configuration n = 2 coil configuration

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Very recently, high beta plasmas transiently reached bN = 4 in 2014 campaign



Values obtained using fully converged KSTAR EFIT reconstructions



High values reached transiently at lowered Bt

 BT in range 0.9 - 1.2 T  bN up to 4 with li ~ 0.8 for

duration longer than tE ~60 ms in these discharges

 bN/li = 5 is ~ 40% over the

computed n = 1 ideal MHD no-wall limit



Adding newly available 3rd neutral beam source may further increase the

• perating performance in the
• ngoing device campaign

KSTAR operating space containing ~11,500 equilibria

li

5 4 3 2 1

bN

0.6 0.8 1.0 1.2 1.4 1.6

2014 KSTAR operation

MP2014-05-02-007 by Sabbagh and Y.S. Park

n = 1 no-wall limit bN > bN

no-wall

bN/li = 5

n = 1 with-wall limit Y.S Park, et al., IAEA FEC 2014 paper EX/P8-05 (Fri. PM) S.W. Yoon, et al., IAEA FEC 2014 paper OV/3-4 (Tues. AM)

18

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Non-resonant Neoclassical Toroidal Viscosity (NTV) physics will be used for the first time in rotation feedback control

19

133743

Plasma rotation (rad/s)

State-space model TRANSP run Plasma rotation (rad/s)

NTV region 2 4 6 104 desired 

t1 t2 t3

t(s) t(s) t1 = 0.34t t2 = 0.91t t3 = 3.01t

yN

0.0 0.2 0.4 0.6 0.8 1.0

NTV torque density (N/m2)

0.0 0.2 0.4 0.6 0.8

(a) (b)

• I. Goumiri (PU), S.A. Sabbagh (Columbia U.), D.A. Gates, S.P. Gerhardt (PPPL)

Feedback using NTV: “n=3” dB(r) spectrum

 

1 2 2 i i i i NBI NTV i i

V V n m R n m R T T t



  r r r r  r



                         

 

 Momentum force balance –  decomposed into Bessel function states  NTV torque:

 

 

 

2 K1 K2 e,i e,i NTV coil

T K f g B n I T d r       

(non-linear)

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Plasma rotation control has been demonstrated for the first time with TRANSP using NBI and NTV actuators

3D coil current and NBI power (actuators)

t (s)

This case uses pre-programmed 3D coil current and NBI feedback

Rotation evolution vs. desired rotation setpoints desired  (#1) desired  (#2)

feedback on Plasma rotation (rad/s) t (s) t (s) t (s) 3D Coil Current (A) NBI power (MW) feedback on

Plasma rotation (rad/s)

20

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Please sign-up for a poster copy

21

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

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Extra slides

22

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

Several ordered publications by K.C. Shaing, et al. led to the “Combined” NTV Formulation

 Publications (chronological order)

1) K.C. Shaing, S.P. Hirschman, and J.D. Callen, Phys. Fluids 29 (1986) 521. 2) K.C. Shaing, Phys. Rev. Lett., 87 (2001) 245003. 3) K.C. Shaing, Phys. Plasmas 10 (2003) 1443. 4) K.C. Shaing, Phys. Plasmas 13 (2006) 052505. 5) K.C. Shaing, S. A. Sabbagh, and M. Peng, Phys. Plasmas 14 (2007) 024501. 6) K.C. Shaing, S. A. Sabbagh, M.S. Chu, et al., Phys. Plasmas 15 (2008) 082505. 7) K.C. Shaing, P. Cahyna, M. Becoulet, et al., Phys. Plasmas 15 (2008) 082506. 8) K.C. Shaing, S. A. Sabbagh, and M. S. Chu, PPCF 51 (2009) 035004. 9) K.C. Shaing, S. A. Sabbagh, and M. S. Chu, PPCF 51 (2009) 035009. 10) K.C. Shaing, S. A. Sabbagh, and M. S. Chu, PPCF 51 (2009) 055003. 11) K.C. Shaing, M. S. Chu, and S. A. Sabbagh, PPCF 51 (2009) 075015. 12) K.C. Shaing, M. S. Chu, and S. A. Sabbagh, PPCF 52 (2010) 025005. 13) K.C. Shaing, S. A. Sabbagh, and M. S. Chu, Nucl. Fusion 50 (2010) 025022. 14) K.C. Shaing, J. Seol, Y.W. Sun, et al., Nucl. Fusion 50 (2010) 125008. 15) K.C. Shaing, M. S. Chu, and S. A. Sabbagh, Nucl. Fusion 50 (2010) 125012. 16) K.C. Shaing, T.H. Tsai, M.S. Chu, et al., Nucl. Fusion 51 (2011) 073043. 17) K.C. Shaing, M.S. Chu, C.T. Hsu, et al., PPCF 54 (2012) 124033.

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 Topic

• Plateau transport
• Island NTV
• Collisional, 1/n regimes
• Banana, 1/n regimes
• Multiple trapping
• Orbit squeezing
• Coll. b’dary layer, n 0.5
• Low n regimes
• Superbanana plateau
• Superbanana regime
• Bounce/transit/drift res.
• Jbootstrap w/resonances
• Combined NTV formula
• B drift in CBL analysis
• Flux/force gen. coords.
• SBP regime refinement
• NTV brief overview

NSTX

25th IAEA Fusion Energy Conference: Characteristics of NTV for Rotation Control / Plasma Response (S.A. Sabbagh, et al.) October 14th, 2014

NSTX-U

EX/1-4: Physical Characteristics of Neoclassical Toroidal Viscosity in Tokamaks for Rotation Control and the Evaluation of Plasma Response

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 Experimental NTV characteristics

 NTV experiments on NSTX and KSTAR  NTV torque TNTV from applied 3D field is a

radially extended, relatively smooth profile

 Perturbation experiments measure TNTV profile

 Aspects of NTV for rotation control

 Varies as dB2; TNTV  Ti

5/2 in primary

collisionality regime for large tokamaks

 No hysteresis on the rotation profile when

altered by non-resonant NTV is key for control

 Rotation controller using NTV and NBI tested

for NSTX-U; model-based design saves power

 NTV analysis to assess plasma response

 Non-resonant NTV quantitatively consistent

with fully-penetrated field assumption

 Surface-averaged 3D field profile from M3D-C1

single fluid model consistent with field used for quantitative NTV agreement in experiment

Highlights

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Perturbation experiments measure NTV torque profile and compare to theory Rotation controller using NTV and NBI