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Title: Neural networks for estimation of divertor conditions in DIII-D using C III imaging

Journal Article · · Nuclear Fusion

Abstract Deep learning approaches have been applied to images of C III emission in the lower divertor of DIII-D to develop models for estimating the level of detachment and magnetic configuration (X-point location and strike point radial location). The poloidal distance from the target to the C III emission front is used to represent the level of detachment. The models perform well on a test dataset not used in training, achieving F 1 scores as high as 0.99 for detachment state classification and root mean squared error (RMSE) as low as 2 cm for front location regression. Predictions for shots with intermittent reattachment are studied, with class activation mapping used to aid in interpretation of the model predictions. Based on the success of these models, a third model was trained to predict the X-point location and strike point radial position from C III images. Though the dataset covers only a small range of possible magnetic configurations, the model shows promising results, achieving RMSE around 1 cm for the test data.

Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
Grant/Contract Number:
AC02-09CH11466
OSTI ID:
2440449
Journal Information:
Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 10 Vol. 64; ISSN 0029-5515
Publisher:
IOP PublishingCopyright Statement
Country of Publication:
IAEA
Language:
English

References (31)

Accelerated version of NUBEAM capabilities in DIII-D using neural networks journal February 2021
Heat flux management via advanced magnetic divertor configurations and divertor detachment journal August 2015
Electron pressure balance in the SOL through the transition to detachment journal August 2015
Advances in radiated power control at DIII-D journal January 2019
Physics basis for the first ITER tungsten divertor journal August 2019
Real-time feedback control of the impurity emission front in tokamak divertor plasmas journal February 2021
Predicting disruptive instabilities in controlled fusion plasmas through deep learning journal April 2019
A tangentially viewing visible TV system for the DIII-D divertor journal January 1997
Optical boundary reconstruction of tokamak plasmas for feedback control of plasma position and shape journal November 2010
Feedback system for divertor impurity seeding based on real-time measurements of surface heat flux in the Alcator C-Mod tokamak journal February 2016
A low energy ion beam facility for mass spectrometer calibration: First results journal January 2018
MANTIS: A real-time quantitative multispectral imaging system for fusion plasmas journal December 2019
Deep convolutional neural networks for multi-scale time-series classification and application to tokamak disruption prediction using raw, high temporal resolution diagnostic data journal June 2020
Progress Toward Interpretable Machine Learning–Based Disruption Predictors Across Tokamaks journal September 2020
On the physics guidelines for a tokamak DEMO journal June 2013
Real-time optical plasma boundary reconstruction for plasma position control at the TCV Tokamak journal May 2014
Partial detachment of high power discharges in ASDEX Upgrade journal April 2015
Real-time capable first principle based modelling of tokamak turbulent transport journal July 2015
Transient heat loads in current fusion experiments, extrapolation to ITER and consequences for its operation journal March 2007
Real-time control of divertor detachment in H-mode with impurity seeding using Langmuir probe feedback in JET-ITER-like wall journal February 2017
Plasma detachment in divertor tokamaks journal February 2018
High-energy ballistic electrons in low-pressure radio-frequency plasmas journal September 2020
Real-time capable modeling of neutral beam injection on NSTX-U using neural networks journal March 2019
Development of a real-time algorithm for detection of the divertor detachment radiation front using multi-spectral imaging journal May 2020
Neural-network accelerated coupled core-pedestal simulations with self-consistent transport of impurities and compatible with ITER IMAS journal December 2020
X-point radiation, its control and an ELM suppressed radiating regime at the ASDEX Upgrade tokamak journal December 2020
Prediction of electron density and pressure profile shapes on NSTX-U using neural networks journal March 2021
Data-driven profile prediction for DIII-D journal March 2021
DIII-D research advancing the physics basis for optimizing the tokamak approach to fusion energy journal October 2021
Physics design of new lower tungsten divertor for long-pulse high-power operations in EAST journal November 2021
Detecting Plasma Detachment in the Wendelstein 7-X Stellarator Using Machine Learning journal December 2021

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