# Presentation: 181159

## Transport and Turbulence Five Year Plan 

- <date/time>

- Transport and Turbulence Five Year Plan

- _S.M. Kaye,_ D. Darrow and the NSTX Team
- PPPL, Princeton University
- Princeton, N.J. 08543
- USA

- Five Year Planning Workshop
- PPPL, Princeton Univ.
- 12-13 Dec. 2002

## NSTX Transport Goals Geared Towards Determining the Attractiveness of the ST and Contributing to Toroidal Transport Physics

- Establish key E and transport scalings
- e- vs i+ transport, dependence on T, ExB
- Assess roles of low- and high-k turbulence in heating and transport
- Assess fast ion confinement
- Influence on neoclassical, turbulent heating and transport
- Determine influence of Er (ExB) on turbulence, L-H
*Use knowledge gained to control plasma transport*
*	**Produce p(r), j(r), for high ****T**, non-inductive current *

## Transport Goals are Related to IPPA Goals

- Five year goal (IPPA 3.1.1)
- Advance the scientific understanding of turbulent transport, forming the basis for a reliable predictive capability in externally controlled systems
- Ten year goal
- Develop fully integrated capability for predicting the performance of externally controlled systems including turbulent transport, macroscopic stability, wave particle physics and multi-phase interfaces

## Three-Pronged Approach to Achieving the Transport Goals in FY03-08

- FY03-08 experimental research plan
- Detailed experiment/theory comparison
- Develop and extend profile and turbulence diagnostics
- Electrostatic, electromagnetic instabilities
- Plasma response
- Continued development of theoretical and numerical tools
- Understand fundamental transport physics
- Develop predictive capability
- Contrast and compare ST with conventional R/a devices (e.g., ITPA)

## NSTX Offers Unique Opportunities

- Low BT  Large gyro-scale lengths, high T
- Low R/a  Large field line pitch on LFS
- Relatively high beam energy  High relative velocity

## NSTX Parameters Challenge Existing Theory Framework

- Local t  1 (75% achieved experimentally in core)
- Electromagnetic effects
- Trapped particle fraction  1
- Validity of fluid treatment of electrons
-  i/L~0.2 (near edge); i~1 to 3 cm
- Validity of spatial scale length ordering
- High B, ExB flow (>200 km/sec)  flow shear (105 to 106/sec)
- Effect on microstability and turbulence characteristics
- Dominant (?) role of electron transport
- Vfast/vAlfven ~3 to 4
- Fast ion driven instabilities (TAE, CAE/GAE)
-  fast/a~1/5-1/3
- Fast ion confinement, non-adiabatic behavior

- ST Features/Theory Issues

- Validity of present gyrokinetic treatment

## Outline

- Experimental studies
- Core transport (global, ions, electrons, momentum, particle/impurity, fast ions)
- Edge transport and fluctuations
- Theory and modeling
- Research plan elements
- Facility and diagnostic upgrades

## Global Confinement Exceeds Predictions from Conventional Aspect Ratio Scalings

- • Eexp from EFIT magnetics reconstruction
-        - Includes fast ion component
- • Quasi-steady conditions

## 	ENSTX-L ~ Ip0.76 BT0.27 PL-0.76

*More accurate determination*
*of R/a dependence needed!*
- Less severe power degradation
- in H-mode E ~ P-0.50
-     - MHD vs confinement limit?
- Different parametric
- dependences for more
- transient L-mode plasmas
-    - Role of rotation?

- 	ENSTX-L ~ Ip0.76 BT0.27 PL-0.76

## Global Confinement - Plans

- FY03: E scalings in RF&NBI, L&H; Eth to ITER DB; R/a dependence in ohmic; start of similarity exp’ts (DIII-D)
- FY04: R/a in NBI intra- and inter-device; transient vs steady-state/role of rotation; rotation control with error field correction coils; dimensionless scalings with t, ; relation of E to q (MSE)
- FY05: Study of rotation dynamics on E (poloidal CHERS)
- FY06: Relation of E on q(r), Er (LIF MSE)
- FY07: Profile control for optimized E; causal relation between rotation, E

## Ti>Te during NBI Indicates Relatively Good Ion Confinement

*T**i**>T**e* during NBI Indicates Relatively Good Ion Confinement

- Pbi ~ 1⁄2 Pbe

- ITG suppressed (GK calculations)
- Ion confinement sometimes “too good”
*Independent validation of T**i** needed*

- TRANSP

## Ion Energy Transport - Plans

- FY03: Establish i baseline (if and when anomalous); start to test role of ITG (Ti/Te, ne(r), ExB dependence); compare to GK
- FY04: Extend ITG study; relation to rotation (error field correction coil); calibrated reflectometry to assess modes for possible stochastic heating; initial assessment wrt to low-k fluctuations
- FY05: Co vs counter to study effect of flow shear, thermal friction pinches; i, ‘ variation by pellet for ITG study; extend study of ion transport/low-k fluctuations
- FY06: Detailed study of ion transport to full-k turbulence; relate transport fluxes to changes in q, Er (LIF MSE)
- FY07-08: Extend studies of ion tranpsort and full k-spectrum of fluctuations; predictive capability based GK/exp’t comparisons

## “Stiff” Te Profiles during Flattop Period with NBI

- Critical marginality?

- ITB w/ HHFW

- Electrons impervious to transport events

## Electron Energy Transport - Plans

- FY03: Establish e baseline
- FY04: Test Te resiliency (modulated HHFW); Assess role of ETG (vary Te/Ti, e, ‘ with RF); relate to q (MSE); compare to GK; initial high-k measurements
- FY05: Extend ETG study with pellets (e, ‘); study effect of flow shear (co vs ctr) using poloidal CHERS; extend high-k comparisons
- FY06: Detailed study of electron transport to full-k turbulence; relate transport fluxes to changes in q, Er (LIF MSE)
- FY07-08: Extend studies of electron transport and full k-spectrum of fluctuations; predictive capability based GK/exp’t comparisons

## Momentum Transport Coupled to Plasma Transport

- Inferred momentum transport low ( < i  neo)
- Temporal increase of E associated with temporal increase of rotation (causality?)

## Momentum Transport - Plans

- FY03: Establish  baseline (edge v + CHERS); initial RF vs NBI comparison
- FY04: Extend RF vs NBI comparison; study effect of error fields on v;study relation of v and q(r) for ITB generation; compare  to GK estimates
- FY05: Co vs ctr/poloidal CHERS for assessment of non-ambipolar losses and flow shear generation
- FY06-08: Relate Er (LIF MSE) to flows (CHERS); study relation of Er, v and q(r) for ITB generation; determine rotation/confinement dynamics causality, study zonal flows
- 	(1 msec CHERS)

## Particle/Impurity Transport Transport Properties Inferred from Perturbative Experiments

- Neon injection: Impurity transport near neoclassical in core

## Impurity/Particle Transport - Plans

- FY03: Impurity gas injection at higher T
- FY04: Supersonic gas injection for impurity transport, make use of USXR, TGS, GEM detectors
- FY05: Deuterium pellet injection for perturbative particle transport
- FY06-08: Extend perturbative experiments with impurity injector

## Fast Ion Confinement Studies Just Starting

- Decay of neutrons consistent with classical slowing down
- Loss rate measurements disagree with modeling
- Variations in neutron rate for nominally similar discharges
- FY03: Overall confinement trends with parameter, L vs H (sFLIP)
- FY04: Control loss fraction (vary gap)
- FY05: Non-ambipolar losses (co vs ctr); power deposition profile with neutron collimators
- FY06-08: Extend studies using an array of solid state detectors

- Results

- Plans

## Edge Characterization and Transport Studies (Including L-H) Have Just Begun 

- L-H transition: Pthresh>Pscal; Ip dependence

- Pth,1~ ne0.61 BT0.78 a0.89 R0.94

- Edge power balance
- indicates inconsistency
- between EFIT separatrix
- location and MPTS

## Radial correlation lengths of
fluctuations related to E

- fluctuations related to E

- Fluctuation Characteristics Related to Plasma Transport

- Convective-cell (“blob”) transport
- potentially significant

- ñ/n goes down from L to H

## Edge Transport and Fluctuations - Plans

- FY03: Submit L-H data to ITER db; study role of Er on transitions with gap, Ip variations, RF; extend radial correlation length, blob studies, edge pedestal characterization
- FY04: Identify dimensionless variables controlling L-H (similarity expts); preliminary assessment of low and high-k turbulence, compare to theory
- FY05: Co vs ctr/poloidal CHERS for assessment of Er on L-H; extend studies of low- and high-k turbulence, comparison with non-linear GK results; extend edge characterization (He beam spectroscopy)
- FY06-08: Role of Er (LIF MSE) extended; full k-spectrum turbulence measurements; edge transport barriers with CT injection; liquid Li/cryopump for density control; extend edge characterization with fast CHERS

## Theory and Modeling - Tools

- Core Transport
- NCLASS neoclassical
- Gyrokinetic codes (GS2, GYRO, GTC)
- Predictive TRANSP (GLF23, M-M, NCLASS)
- Edge Transport (diffusive and non-diffusive transport)
- BAL
- BOUT
- UEDGE

## Theory and Modeling - Plans

- FY03: Predictive TRANSP using analytic estimates of ’s; validate GK codes in low R/a regime (benchmark); update neoclassical (beam-thermal friction, large /L); non-adiabatic fast ions; edge transport modeling
- FY04: Predictive TRANSP analysis with ’s from non-linear GK runs; incorporate large *, T, fT, shaping effects into GK codes; non-linear calcs of CAE mode amplitudes; start to compare turbulence measurements to theory
- FY05: Incorporate ExB, non-local effects in GK; extend theory/exp’t comparison of turbulence; start developing anomalous heating models
- FY06-08: Start to develop high-confidence predictive capability; combine with MHD stability to form self-consistent package for integrated scenario development

## Transport physics

- He beam spectroscopy

*Transport physics*

- MSE CIF

- MSE LIF (J, Er, P); polarimetry

- CHERS 51 ch

- Error field coils

- 1 – 3 MW EBW

- V shear  & w/error field

- Confinement scalings

- Momentum & power balance, strong electon & ion heating, low and high beta

- Local transport & turbulence
- Low/high k  spectra theory/experiment, lo/high beta

- Feedback with MSE, heating, CD, rtEFIT

*Transport tools*

- Poloidal CHERS

- Turbulence diagnostics
-               *Initial                     Advanced*

- Boundary transport & turbulence

- D pellets

- Li pellets

- Feedback with heating, CD, V, fueling

-  & pellets

*Understanding*

*P(r),J**BS** optimize*

- Poloidal flows

- Pedestal characterize

- Cryopump

- Liquid Li?
- CT injection?

- MPTS upgrades

- FY03

- 04

- 05

- 06

- 07

- 08

- 09

***IPPA: 5 year***

***IPPA: 10 yr***

*Transport theory*

- Predictive Transp (GLF23, Multi-Mode)

- GS2 linear, non-linear

- GTC trapped e-     Finite           High 

- Gyro                             non-adiabatic e-

- Neoclassical: beam-thermal friction, potato orbit, high /L, Bpol/Btor

-        Non-linear CAE                                  Anomalous heating models

*Full predictive transport simulationsS*

- Imaging X-ray crystal

- Neutron collimator

- Fast CHERS (edge)

- He beam spectroscopy

- Impurity injector

- Solid state neutral particle detectors

- Edge v

## Slide 26

## Transport physics

- He beam spectroscopy

*Transport physics*

- MSE CIF

- MSE LIF (J, Er, P); polarimetry

- CHERS 51 ch

- Error field coils

- 1 – 3 MW EBW

- V shear  & w/error field

- Confinement scalings

- Momentum & power balance, strong electon & ion heating, low and high beta

- Local transport & turbulence
- Low/high k  spectra theory/experiment, lo/high beta

- Feedback with MSE, heating, CD, rtEFIT

*Transport tools*

- Poloidal CHERS

- Turbulence diagnostics
-               *Initial                                  Advanced*

- Boundary transport & turbulence

- D pellets

- Li pellets

- Feedback with heating, CD, V, fueling

-  & pellets

*Understanding*

*P(r),J**BS** optimize*

- Poloidal flows

- Pedestal characterize, optimize

- Cryopump

- Liquid Li?
- CT injection?

- MPTS upgrades

- FY03

- 04

- 05

- 06

- 07

- 08

- 09

***IPPA: 5 year***

***IPPA: 10 yr***

*Transport theory*

- Predictive Transp (GLF23, Multi-Mode)

- GS2 linear, non-linear

- GTC trapped e-     Finite           High 

- Gyro                             non-adiabatic e-

- Neoclassical: beam-thermal friction, potato orbit, high /L, Bpol/Btor

-        Non-linear CAE                                  Anomalous heating models

*Full predictive transport simulations*

- Imaging X-ray crystal

- Neutron collimator

- Fast CHERS (edge)

- He beam spectroscopy

- Impurity injector

- Solid state neutral particle detectors

- Edge v