ITPA TC-15, Dependence of Momentum and Particle Pinch on Collisionality, R/L n and q

AssociationEuratom–Tekes

ITPA TC-15, Dependence of Momentum and Particle Pinch on Collisionality, R/Ln and q

T. Tala (JET, DIII-D, C-Mod, AUG), W. Solomon (DIII-D, JET, NSTX), S. Kaye (NSTX), A. Salmi (JET, DIII-D), J. Rice (C-Mod), Y. Podpaly (C-Mod), R.

McDermott (AUG), G. Tardini (AUG), M. Yoshida (JT-60U),

C. Angioni (theory)

+ large local teams in each tokamak not listed here

VTT TECHNICAL RESEARCH CENTRE OF FINLAND

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Status of TC-15 Joint Experiment: Dependence of Momentum and Particle Pinch on Collisionality

Colour codes:XXX Experiment done, more proposedXXX Experiment finishedXXX Experiment allocated timeXXX Some data exist, but not directly linked to this Joint Experiment

Device Momentum Particle Period Local Key Person

JET, 22 October 2009

XXX XXX 2009-2011 T. Tala / L. Garzotti

DIII-D, 20 May 2009

XXX XXX 2009-2010 W. Solomon / L. Zeng

NSTX, August 2009 XXX XXX 2009-2010 S. Kaye / L. Delgado-Aparicio

AUG, 1 and 3 February 2011

XXX 2010-2011 R. McDermott

C-MOD, 13 January 2011

XXX 2010-2011 J. Rice / Y. Podpaly

JT-60U XXX 2009-2010 M. Yoshida


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Outline

JET

AUG

DIII-D

C-Mod

Summary and Future Plans


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JET Analysis Progressed Well, NF Paper Is Being Written

Pinch number Rvpinch/χ depends strongly on the density gradient length R/Ln

Rvpinch/χ ≈ 1.2R/Ln + 1.4

Similar dependence of the pinch on R/Ln also found in JET rotation database studies [P. de Vries, PPFC 2010, H. Weisen, EU-US TTF 2010]

GS2 simulations find similar positive trend with R/Ln, but it is weaker and very dependent on the value of R/Ln (note the large error bars in R/Ln)

Data averaged over the region from r/a=0.4 to r/a=0.8


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Outline

JET

AUG

DIII-D

C-Mod



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ITPA TC-15 Partly Carried Out on AUG in February 2011

Modulation signal very clear and at optimum level (~5%) – demonstrating feasibility of NBI modulation technique on AUG

Compare cases with NBI, NBI+ICRH/ECRH clear differences in phase and amplitude with ion

versus electron heating momentum transport and possibly also torque

sources changed by RF


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The Fraction of J×B torque and Collisional Torque Different on AUG than on JET and DIII-D

AUG pulse number 26241, torque from TRANSP

J×B torque collisional torquetotal torque


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Data from Pulse no. 26241 Demonstrates the Existence of the Momentum Pinch on AUG

experimental modulation data simulation with Prandtl number ≈ 0.7, vpinch=0simulation with Prandtl number ≈ 1.3, vpinch ≈ 10m/s

Sawtooth significant inside r/a<0.2 and is coupled to the modulation frequency

Analysis valid only at r/a>0.3


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Prandtl and Pinch Number Profiles of 26241

simulation with Prandtl number ≈ 0.7, vpinch= 0simulation with Prandtl number ≈ 1.3, vpinch ≈ 10m/s


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Outline

JET

AUG

DIII-D

C-Mod



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Clear Rotation Modulation Signal at r/a>0.3 on DIII-D, but Wild Things Happen at r/a<0.3

DIII-D pulse number 137341


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Similar Test to AUG on DIII-D to See What Kind of Pinch Is Needed to Reproduce the Experimental Data


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Similarly to AUG, without the Pinch, Phase Significantly Overestimated; with the Pinch, Phase Is Matched Well on DIII-D


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Outline

JET

AUG

DIII-D

C-Mod



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Diagnostics NBI Did Not Produce Any Observable Rotation Perturbation on C-Mod

Time (s)


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LHCD Modulation Creates a Large Rotation Perturbation, but It Also Perturbs ne,Te and Ti

Time (s)


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Septum Modulation (Upper-Lower Null) Can Create a Non-Perturbative Rotation Modulation on C-Mod, Further Optimization Needed

Time (s)


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Outline

JET

AUG

DIII-D

C-Mod



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2011 Activities for the ITPA TC-15 Experiment, Lots of Progress both on the Experimental and Analysis Sides on JET, AUG, DIII-D and C-Mod

JET: Finalizing the work on the parametric dependencies of the pinch and Prandtl number (NF paper). New experiments to study the β dependence of momentum pinch (TC-16) proposed for 2012-2013.

DIII-D: Detailed momentum transport study using the same automated analysis technique as in JET for the NBI modulation experiment in progress. β dependence experiment (TC-16) on DIII-D proposed. First set of data published by W. Solomon et al. in PoP 2010.

AUG: About 60-70% of the TC-16 experiment performed in February 2011. The rest of TC-15 planned next week (April 12), possibly including the β dependence extension (TC-16). Initial data quality looks very good, physics scans somewhat limited by the operational space on AUG. Some data to be included in Rachael McDermott’s EPS 2011 paper.

C-Mod: A session on initial survey of different rotation perturbation techniques performed in January 2011. Septum sweeping found to be a promising technique. Next session (target autumn 2011) will exploit SSEP technique, with the aim to scan collisionality, density etc.

NSTX: Experiment performed in 2009 and analysis finished, and partly published by W. Solomon et al. in PoP 2010. Particle transport part reported in IAEA 2010 (L. Delgado-Aparacio)


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Long Term Plans

Finish the experiments (mostly in 2011)

Carry out the detailed momentum transport analysis using identical tools for AUG, DIII-D and JET

Write an IAEA 2012 paper on the joint analysis including the multi-tokamak scans of collisionality, R/Ln, q, density, …

Close the TC-15 JEX in the autumn 2012

ITPA TC-15, Dependence of Momentum and Particle Pinch on Collisionality, R/L n and q

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