Effects of twodimensional magnetic uncertainties and threedimensional error and perturbation fields on the Small Angle Slot divertor geometry and topology [Effects of two and threedimensional magnetic fields on the Small Angle Slot divertor magnetic topology]
The Small Angle Slot (SAS) was recently installed on DIIID as an advanced divertor, promising easier plasma detachment and lower temperatures across the whole target. A twofold study of the SAS magnetic topology is presented in this paper. On one hand, a twodimensional uncertainty quantification analysis is carried out through a Monte Carlo approach in order to understand the level of accuracy of twodimensional equilibrium computations in reconstructing the strike point and angle onto the divertor. Under typical experimental conditions, the uncertainties are found to be roughly 6.8 mm and 0.56 deg, respectively. On the other hand, a threedimensional “vacuum” analysis is carried out to understand the effects of typical external perturbation fields on the scrapeoff layer topology. When the threedimensional Icoils are switched on, poloidallylocalized lobes are found to appear, grow, and hit the SAS target, although barely, even for 5 kA; at the same time, the strike point modulation is found to be roughly 1.8 mm and thus negligible for most purposes. Furthermore, such results complement previous twodimensional analyses in characterizing typical SAS equilibria and provide useful background information for planning and interpreting SAS experiments.
 Authors:

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 Oak Ridge Associated Univ., Oak Ridge, TN (United States); General Atomics, San Diego, CA (United States)
 General Atomics, San Diego, CA (United States)
 Univ. of CaliforniaSan Diego, San Diego, CA (United States)
 Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
 Publication Date:
 Grant/Contract Number:
 FC0204ER54698; AC0500OR22725
 Type:
 Accepted Manuscript
 Journal Name:
 Nuclear Fusion
 Additional Journal Information:
 Journal Volume: 58; Journal Issue: 2; Journal ID: ISSN 00295515
 Publisher:
 IOP Science
 Research Org:
 General Atomics, San Diego, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
 Sponsoring Org:
 USDOE Office of Nuclear Energy (NE)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; plasma physics; DIIID; magnetic topology; divertor footprint
 OSTI Identifier:
 1415991
 Alternate Identifier(s):
 OSTI ID: 1422607
Trevisan, Gregorio L., Lao, Lang L., Evans, Todd E., Guo, Hou Yang, Orlov, Dmitry M., Strait, Edward J., Wingen, Andreas, and Wu, Wen. Effects of twodimensional magnetic uncertainties and threedimensional error and perturbation fields on the Small Angle Slot divertor geometry and topology [Effects of two and threedimensional magnetic fields on the Small Angle Slot divertor magnetic topology]. United States: N. p.,
Web. doi:10.1088/17414326/aa9dab.
Trevisan, Gregorio L., Lao, Lang L., Evans, Todd E., Guo, Hou Yang, Orlov, Dmitry M., Strait, Edward J., Wingen, Andreas, & Wu, Wen. Effects of twodimensional magnetic uncertainties and threedimensional error and perturbation fields on the Small Angle Slot divertor geometry and topology [Effects of two and threedimensional magnetic fields on the Small Angle Slot divertor magnetic topology]. United States. doi:10.1088/17414326/aa9dab.
Trevisan, Gregorio L., Lao, Lang L., Evans, Todd E., Guo, Hou Yang, Orlov, Dmitry M., Strait, Edward J., Wingen, Andreas, and Wu, Wen. 2018.
"Effects of twodimensional magnetic uncertainties and threedimensional error and perturbation fields on the Small Angle Slot divertor geometry and topology [Effects of two and threedimensional magnetic fields on the Small Angle Slot divertor magnetic topology]". United States.
doi:10.1088/17414326/aa9dab.
@article{osti_1415991,
title = {Effects of twodimensional magnetic uncertainties and threedimensional error and perturbation fields on the Small Angle Slot divertor geometry and topology [Effects of two and threedimensional magnetic fields on the Small Angle Slot divertor magnetic topology]},
author = {Trevisan, Gregorio L. and Lao, Lang L. and Evans, Todd E. and Guo, Hou Yang and Orlov, Dmitry M. and Strait, Edward J. and Wingen, Andreas and Wu, Wen},
abstractNote = {The Small Angle Slot (SAS) was recently installed on DIIID as an advanced divertor, promising easier plasma detachment and lower temperatures across the whole target. A twofold study of the SAS magnetic topology is presented in this paper. On one hand, a twodimensional uncertainty quantification analysis is carried out through a Monte Carlo approach in order to understand the level of accuracy of twodimensional equilibrium computations in reconstructing the strike point and angle onto the divertor. Under typical experimental conditions, the uncertainties are found to be roughly 6.8 mm and 0.56 deg, respectively. On the other hand, a threedimensional “vacuum” analysis is carried out to understand the effects of typical external perturbation fields on the scrapeoff layer topology. When the threedimensional Icoils are switched on, poloidallylocalized lobes are found to appear, grow, and hit the SAS target, although barely, even for 5 kA; at the same time, the strike point modulation is found to be roughly 1.8 mm and thus negligible for most purposes. Furthermore, such results complement previous twodimensional analyses in characterizing typical SAS equilibria and provide useful background information for planning and interpreting SAS experiments.},
doi = {10.1088/17414326/aa9dab},
journal = {Nuclear Fusion},
number = 2,
volume = 58,
place = {United States},
year = {2018},
month = {1}
}