Abstract
Al injection with an LBO system has been used to diagnose impurity transport in the edge of H-mode plasmas with and without RMPs. For the discharges with RMPs, after the initial rise, nAl decreases at a steady rate in the pedestal. However, for the naturally ELMy discharge without RMPs, nAl continues to increase after the initial rise and only decreases during ELMs. STRAHL calculations show that the discharges with RMPs have increased diffusion near the plasma edge, which prevents the build up of impurities in the pedestal. For the case of the naturally ELMy discharge, diffusion near the plasma edge is low during the inter-ELM period and the majority of impurity ejection occurs during ELMs. W injection into a discharge without RMPs had a more deleterious effect on plasma performance than injection of a similar number of W atoms into a plasma with RMPs. The discharge without RMPs experienced a radiative collapse, with the plasma temperature cooling from the outside in. Discharges with RMPs did not experience a radiative collapse or a decrease in pedestal temperature due to the increased diffusion in the pedestal region from the RMPs.
Original language | English |
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State | Published - 2019 |
Externally published | Yes |
Event | 46th European Physical Society Conference on Plasma Physics, EPS 2019 - Milan, Italy Duration: Jul 8 2019 → Jul 12 2019 |
Conference
Conference | 46th European Physical Society Conference on Plasma Physics, EPS 2019 |
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Country/Territory | Italy |
City | Milan |
Period | 07/8/19 → 07/12/19 |
Funding
This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under Award DE-FC02-04ER54698. Disclaimer: This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trade-mark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.