1 / 8

Scaling of impurity (Ne & Ar) transport in beam heated NSTX H-mode discharges

Scaling of impurity (Ne & Ar) transport in beam heated NSTX H-mode discharges. L. F. Delgado-Aparicio, D. Stutman, K. Tritz, and M. Finkenthal The Johns Hopkins University, The Plasma Spectroscopy Group R. E. Bell, R. Kaita, S. Kaye, B. P. LeBlanc, S. Paul, L. Roquemore and D. Smith

nero
Download Presentation

Scaling of impurity (Ne & Ar) transport in beam heated NSTX H-mode discharges

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Scaling of impurity (Ne & Ar) transport in beam heated NSTX H-mode discharges L. F. Delgado-Aparicio, D. Stutman, K. Tritz, and M. Finkenthal The Johns Hopkins University, The Plasma Spectroscopy Group R. E. Bell, R. Kaita, S. Kaye, B. P. LeBlanc, S. Paul, L. Roquemore and D. Smith Princeton Plasma Physics Laboratory F. Levinton, H. YuhNOVA Photonics, Inc. NSTX, results meeting Monday, July 22, 2007 Princeton, New Jersey, USA

  2. Abstract • Motivation • Perform particle transport studies in high (Power & b) performance • NSTX H-modes, important for NSTX and the next-step ST. • DZ (diffusion) & vZ (convective velocity) • Identify regimes with possible impurity “screening” (vZ>0). • r* scaling at fixed q-profile, • Ip and Bf scaling • Experiment • i) Neon injected in MHD quiescent high-b, high confinement H-modes. • ii) The main diagnostic used was the “multi-color” optical SXR array. • iii) B & Ip scanned at fixed q-profile for r* scaling experiments.

  3. Experimental requirements and issues during XP 716 • Experimental requirements • Sources A & B @ 90 kV, and source C @ 70 kV • Turn of source C @ 300 ms • Impurity injection @ 350 ms • Issues during XP 716 • Source B had to be turned off. Worked at 4 MW with sources A & C • Multiple ELMs and possible inboard MARFE activity • Try to reduce the ELM activity by changing the CS fueling • MHD activity in 5.5 kG shots • H-mode  L-mode  H-mode (change timings) • Impossible to achieve good conditions @ 0.8 MA  0.9 MA • Control access for TVPS PLC • Failed to open shutters (TIVs) for good Ar injection!

  4. Neon injection at 4.5 kG and 1.0 MA (121032 & 121031) Did MHD [e.g. ELMs, MARFEs or (m,n) modes] shield the core from impurities? Neon, t[400,406]ms CORE MID-RADIUS EDGE

  5. Argon injection at 4.5 kG and 1.0 MA (121036 & 121035) Argon, t[400,410]ms CORE MID-RADIUS EDGE

  6. Neon injection at 5.5 kG and 1.0 MA (121017 & 121015) Neon, t[350,360]ms CORE MID-RADIUS EDGE

  7. Neon injection at 5.5 kG and 1.2 MA (121030 & 121029) • Background: H-L-H-mode conditions @ 390 ms. tE and Sn increased strongly when in L-mode • Neon seeded: Do not have the H-L-H transitions. tE and Sn increased when gas is injected! Neon, t[420,430]ms CORE MID-RADIUS EDGE MHD

  8. Future work • Invert line-integrated data to obtain SXR emissivity profiles. • Run MIST code. Possible need of time-dependent (DZ & VZ) analysis. • Establish (if possible) impurity scaling at 4.5 kG and 1.0 MA. • Investigate the role of MHD and ELMs in shielding the core. • Study the transport reduction at high current during the Ip scaling (5.5 kG – 1.0 MA vs. 5.5 kG – 1.2 MA) • Find out why tE and Sn increased when gas was injected.

More Related