Overview of the physics and engineering design of NSTX upgrade

Ménard, J.; Gerhardt, S. P.; Bell, M.G.; Bialek, J.; Brooks, A.; Canik, J.; Chrzanowski, J.; Denault, M.; Dudek, L.; Gates, D.; Gorelenkov, N. N.; Guttenfelder, W.; Hatcher, R.; Hosea, J.; Kaita, R.; Kaye, S. M.; Kessel, C.; Kolemen, Egemen; Kugel, H.; Maingi, R.; Mardenfeld, Mike; Mueller, D.; Nelson, B. A.; Neumeyer, C.; Ono, M.; Perry, E.; Ramakrishnan, R.; Raman, R.; Ren, Y.; Sabbagh, S. A.; Smith, M.; Soukhanovskii, V.; Stevenson, T.; Strykowsky, R.; Stutman, D.; Taylor, G.; Titus, P.; Tresemer, K.; Tritz, K.; Viola, M.; Williams, M. D.; Woolley, R.; Yuh, H.; Zhang, H.; Zhai, Yuhu; Zolfaghari, A.

doi:10.1088/0029-5515/52/8/083015

Cited by 187 publications

(183 citation statements)

References 194 publications

Supporting

Mentioning

178

Contrasting

Order By: Relevance

“…This scaling predicts improved confinement at smaller values of ν * envisioned for next generation STs [41,42]. It is important to clarify the cause of this scaling and whether it will hold at lower ν * [43].…”

Section: Introductionmentioning

confidence: 88%

Simulation Of Microtearing Turbulence In NSTX

Guttenfelder¹,

Kaye²,

Nevins³

et al. 2012

View full text Add to dashboard Cite

Thermal energy confinement times in NSTX dimensionless parameter scans increase with decreasing collisionality. While ion thermal transport is neoclassical, the source of anomalous electron thermal transport in these discharges remains unclear, leading to considerable uncertainty when extrapolating to future ST devices at much lower collisionality.Linear gyrokinetic simulations find microtearing modes to be unstable in high collisionality discharges. First non-linear gyrokinetic simulations of microtearing turbulence in NSTX show they can yield experimental levels of transport. Magnetic flutter is responsible for almost all the transport (~98%), perturbed field line trajectories are globally stochastic, and a test particle stochastic transport model agrees to within 25% of the simulated transport. Most significantly, microtearing transport is predicted to increase with electron collisionality, consistent with the observed NSTX confinement scaling. While this suggests microtearing modes may be the source of electron thermal transport, the predictions are also very sensitive to electron temperature gradient, indicating the scaling of the instability threshold is important. In addition, microtearing turbulence is susceptible to suppression via sheared E×B flows as experimental values of E×B shear (comparable to the linear growth rates) dramatically reduce the transport below experimental values. Refinements in numerical resolution and physics model assumptions are expected to minimize the apparent discrepancy. In cases where the predicted transport is strong, calculations suggest that a proposed polarimetry diagnostic may be sensitive to the magnetic perturbations associated with the unique structure of microtearing turbulence.

show abstract

Section: Introductionmentioning

confidence: 88%

Simulation Of Microtearing Turbulence In NSTX

Guttenfelder¹,

Kaye²,

Nevins³

et al. 2012

View full text Add to dashboard Cite

show abstract

“…An comprehensive overview of the NSTX-Upgrade physics motivation and engineering design is given in Ref. [45]. This section describes briefly those upgrades relevant to the present study.…”

Section: : the Nstx-upgrade Facilitymentioning

confidence: 99%

“…Structural improvements required for safe operations at these higher fields and currents are described in Ref. [45]. As illustrated in Fig.…”

Section: : the Nstx-upgrade Facilitymentioning

confidence: 99%

“…As will be discussed in great detail throughout this paper, the increased heating power is only one motivation for this addition. Equally important, the new beamline is steered to have a significantly larger beam tangency radius, which improves the current drive efficiency and provides the option for off-axis NBCD [41,45].…”

Section: : the Nstx-upgrade Facilitymentioning

confidence: 99%

“…The NSTX-Upgrade facility [45] has been designed to address these and other critical issues. There are two primary components to this upgrade of the existing NSTX device.…”

Section: : Introduction and Motivationmentioning

confidence: 99%

See 2 more Smart Citations

Exploration of the Equilibrium Operating Space For NSTX-Upgrade

Gerhardt¹

2012

View full text Add to dashboard Cite

Multi‐Fluid Transport Modeling of NSTX Upgrade Standard and Snowflake Divertor Configurations

Meier

Soukhanovskii

Gerhardt

et al. 2014

Contrib. Plasma Phys.

Self Cite

View full text Add to dashboard Cite

In NSTX Upgrade (NSTX-U), power exhaust is expected to challenge available material and heat removal technologies, which are limited to ∼10 MW/m 2 . Preliminary analysis of heat flux mitigation strategies, including the snowflake divertor configuration and radiative divertor operation, is performed with the multi-fluid edge transport code, UEDGE. Divertor recycling between 95% and 99%, and power exhaust between 7 and 9 MW are explored. Compared to the standard divertor, the particular snowflake divertor studied here strongly reduces outer target heat flux, but tends to have higher (>10 MW/m 2 ) inner target heat flux. This suggests that snowflake divertor optimization should be pursued in future work. Both neon and argon impurity seeding scenarios mitigate high heat fluxes in both standard and snowflake configurations, but argon can cause radiative collapse of the core plasma at only 3% concentration. Divertor cryopumping is also considered, and modeling shows ∼50% more particle removal with the snowflake divertor.

show abstract

Overview of the physics and engineering design of NSTX upgrade

Cited by 187 publications

References 194 publications

Simulation Of Microtearing Turbulence In NSTX

Simulation Of Microtearing Turbulence In NSTX

Exploration of the Equilibrium Operating Space For NSTX-Upgrade

Multi‐Fluid Transport Modeling of NSTX Upgrade Standard and Snowflake Divertor Configurations

Contact Info

Product

Resources

About