Publications

Jul, 2024

Journal

Experiments on plasma detachment in a V-shaped slot divertor in the DIII-D tokamak

Jun, 2024

Journal

Reversed-direction 2-point modelling applied to divertor conditions in DIII-D*

A predictive form of the extended 2-point model known as the 'reverse 2-point model', Rev2PM, is applied to a range of detachment levels in the open lower divertor of DIII-D, showing that the experimentally measured electron temperature (Te) and pressure (pe) at the divertor entrance can be calculated within 50% from target measurements, if and only if a posteriori correct…

Dec, 2023

Journal

DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy

DIII-D physics research addresses critical challenges for the operation of ITER and the next generation of fusion energy devices. This is done through a focus on innovations to provide solutions for high performance long pulse operation, coupled with fundamental plasma physics understanding and model validation, to drive scenario development by integrating high performance…

Dec, 2023

Journal

DIII-D research towards establishing the scientific basis for future fusion reactors

DIII-D research is addressing critical challenges in preparation for ITER and the next generation of fusion devices through focusing on plasma physics fundamentals that underpin key fusion goals, understanding the interaction of disparate core and boundary plasma physics, and developing integrated scenarios for achieving high performance fusion regimes. Fundamental investi…

Nov, 2023

Journal

Measurements of three-dimensional flows induced by magnetic islands

Magnetic reconnection and the resulting complex magnetic field geometries are fundamental aspects of our understanding of both space and laboratory plasmas. We report on the observation of three-dimensional (3D) impurity ion flow perturbation due to counterstreaming flows in the boundary plasma of the DIII-D tokamak. These counterstreaming flows arise not due to the magnet…

Nov, 2023

Journal

Numerical assessment of the new V-shape small-angle slot divertor on DIII-D

The small-angle slot (SAS) divertor of the DIII-D tokamak, and its upcoming upgrade, the V-shape small-angle slot (SAS-V) divertor, are numerically investigated using the SOLPS-ITER code package, including the effect of particle drifts, for a range of plasma density, heating power, strike point position in the slot, and for both magnetic field directions. The simulations s…

Nov, 2023

Journal

First experimental tests of a new small angle slot divertor on DIII-D

A new small angle slot (SAS) divertor concept has been developed to enhance neutral cooling across the divertor target by coupling a closed slot structure with appropriate target shaping. Initial tests on DIII-D find a strong interplay between such anticipated 'SAS' effects and cross-field drifts, favouring operation with the ion B  ×  ∇B drift away from the X-point, as cu…

Nov, 2023

Journal

Separating divertor closure effects on divertor detachment and pedestal shape in DIII-D

Comparison between an open divertor and a more-closed divertor in DIII-D demonstrates detachment up to 40% lower pedestal density (ne,ped) in the closed divertor due to a combination of decreased fueling of the pedestal and increased dissipation in the scrape off layer (SOL) in the closed divertor, both resulting from increased neutral trapping in the divertor. Predicting…

Nov, 2023

Journal

Predicting the rotation profile in ITER

Determining the toroidal rotation for future tokamaks like ITER is a challenging and important problem. By combining empirical scalings for the intrinsic rotation at the top of the pedestal with the expected neutral beam torque and modeling of momentum transport, the toroidal rotation profile for ITER is predicted with TGYRO using TGLF (SAT0 and SAT1). On axis rotation exc…

Nov, 2023

Journal

Improved core-edge compatibility using impurity seeding in the small angle slot (SAS) divertor at DIII-D

Impurity seeding studies in the small angle slot (SAS) divertor at DIII-D have revealed a strong relationship between the detachment onset and pedestal characteristics with both target geometry and impurity species. N2 seeding in the slot has led to the first simultaneous observation of detachment on the entire suite of boundary diagnostics viewing the SAS without degradat…

Nov, 2023

Journal

Dependence of neutral pressure on detachment in the small angle slot divertor at DIII-D

Local neutral pressure measurements in the closed small angle slot (SAS) divertor [1,2] on DIII-D show a large increase when the divertor plasma shifts from high recycling into detachment. In-tile pressure gauges were installed to measure the pressure in the near- and far-SOL regions to examine the predicted high neutral pressures and compression. Cross-field drift effects…

Nov, 2023

Journal

3D equilibrium reconstruction with islands

This paper presents the development of a 3D equilibrium reconstruction tool and the results of the first-ever reconstruction of an island equilibrium. The SIESTA non-nested equilibrium solver has been coupled to the V3FIT 3D equilibrium reconstruction code. Computed from a coupled VMEC and SIESTA model, synthetic signals are matched to measured signals by finding an optima…