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

L. F. Delgado-Aparicio, D. Stutman, K. Tritz, and M. FinkenthalThe 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.

J. Lepson and P. BeiersdorferUniversity of California - Berkeley & Lawrence Livermore National Laboratory

NSTX, XP 613 (2007 T&T Review)March 27th, 2007

Princeton, New Jersey, USA

GOAL: Continue with the particle transport characterization of H-mode plasmas

GOAL: Continue with the particle transport characterization of H-mode plasmas

(L. F. Delgado-Aparicio, APS-DPP, 2006)

Diffusion• Dneon 1/B2 satisfying neoclassical scaling

laws and Dneon ~ Di, i,(TRANSP).

Convective velocity• The initial slow core penetration (~100ms)

with a peaking of neon density late in time (NSTX # 121165NSTX # 121165), suggests the presence of an inward pinch (convective) velocity.

• For the high field case (NSTX # 121174NSTX # 121174), the positive (radially outwards) convective velocity explains the “shielded” low level of impurities in NSTX inner half.

First estimates of First estimates of DD and and VVCC in in ** scaling experiments scaling experiments

Type of plasmas neededType of plasmas needed

NBI requirements• Sources A & B @ 90 kV, and source C @ 70 kV

• Turn of source C @ 300 ms

NSTX 121154, 121162, 4.5 kG, 1.0 MA NSTX 121154, 121162, 4.5 kG, 1.0 MA

Shot matrix for 1st half of the day (Neon injections)

Dial 2006 baseline + Ne injection (121154/121162 but @ 5.5 kG, 1.0 MA)

2 shots

Baseline + Ne injection(5.5 kG, 1.2 MA)

2 shot

Baseline + Ne injection(5.5 kG, 0.9 MA)

2 shots

Baseline + Ne injection(4.5 kG, 0.9 MA)

2 shots

Baseline + Ne injection(4.0 kG, 0.9 MA)

2 shots

Sub-total 10 shots

• Neon injections @ 350 ms for t~50 ms, 1.5Torr·l/s

• Controlled access to change gases (for Ar injection): ~60 minutes ?

Ip scaling at B=5.5 kG

B scaling at Ip=0.9 MA

Shot matrix for 2nd half of the day (Argon injections)

Dial 2006 baseline + Ar injection (121154/121162, 4.5 kG, 1.0 MA)

2 shots

Baseline + Ar injection(4.0 kG, 0.9 MA)

2 shot

Baseline + Ar injection(5.5 kG, 1.2 MA)

2 shots

Baseline + Ar injection(5.5 kG, 0.9 MA)

2 shots

Sub-total 8 shots

Compare with 2006 Ne

injections @ ~constant BIp

2-point B and Ip scaling to

compare with neon

• Argon injections @ 350 ms for t~50 ms, 0.5 Torr·l/s

• If time permits: a) repeat 4.5 kG, 1.0 MA but for injection at 0.75 Torr·l/s b) include 5.5 kG, 1.0 MA & 4.5 kG, 0.9 MA

• D. Gates wants to asses the impact of Ar injection in the background plasma