Abstract
| Language | English |
|---|---|
| Pages | 479-488 |
| Number of pages | 10 |
| Journal | Plasma Physics and Controlled Fusion |
| Volume | 48 |
| Issue number | 4 |
| DOIs | |
| Publication status | Published - 1 Apr 2006 |
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Keywords
- spherical tokamaks
- boundary layer effects
- plasma-material interactions
- plasma devices
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H-mode access in the low density regime on JET. / Andrew, Y.; Sartori, R.; Righi, E.; De la Luna, E.; Hacquin, S.; Howell, D.F.; Hawkes, N.C.; Horton, L.D.; Huber, A.; Korotkov, A.; O'Mullane, M.G.; Contributors, JET EFDA.
In: Plasma Physics and Controlled Fusion, Vol. 48, No. 4, 01.04.2006, p. 479-488.Research output: Contribution to journal › Article
TY - JOUR
T1 - H-mode access in the low density regime on JET
AU - Andrew, Y.
AU - Sartori, R.
AU - Righi, E.
AU - De la Luna, E.
AU - Hacquin, S.
AU - Howell, D.F.
AU - Hawkes, N.C.
AU - Horton, L.D.
AU - Huber, A.
AU - Korotkov, A.
AU - O'Mullane, M.G.
AU - Contributors, JET EFDA
PY - 2006/4/1
Y1 - 2006/4/1
N2 - 1 H-mode access studies under conditions of very low plasma density provide valuable information on the, physics of the edge transport barrier formation and are an important part of the operational scenario development for the next step fusion device, ITER. JET operation with a very low edge electron density, (n) over bar (e) = 0.8-1.4 x 10(19) m(-3), with the MkII gas box septum divertor was found to have a significant effect on the power threshold for the L-H transition, P-th. A sharp `turning point' below which P-th increases with decreasing (n) over bar (e) is found for I-p/B-t values of 2.5 MA/2.7 T, 2.5 MA/2.6T 2.5 MA/2.4T and 2.2 MA/2.4T. The pedestal electron temperature demonstrates a very similar dependence on the edge (n) over tilde (e) as P-th. The role of Z(eff) in the variation of the H-mode power threshold with density is also considered. Shots with the divertor septum present are compared with an identical (n) over bar (e) scan, run with the MkII GB septum replacement plate divertor at 2.5 MA/2.7 T and 2.5 MA/2.6 T. The results from this investigation indicate that removal of the septum may have lowered the (n) over tilde (e) `turning point' for P-th.
AB - 1 H-mode access studies under conditions of very low plasma density provide valuable information on the, physics of the edge transport barrier formation and are an important part of the operational scenario development for the next step fusion device, ITER. JET operation with a very low edge electron density, (n) over bar (e) = 0.8-1.4 x 10(19) m(-3), with the MkII gas box septum divertor was found to have a significant effect on the power threshold for the L-H transition, P-th. A sharp `turning point' below which P-th increases with decreasing (n) over bar (e) is found for I-p/B-t values of 2.5 MA/2.7 T, 2.5 MA/2.6T 2.5 MA/2.4T and 2.2 MA/2.4T. The pedestal electron temperature demonstrates a very similar dependence on the edge (n) over tilde (e) as P-th. The role of Z(eff) in the variation of the H-mode power threshold with density is also considered. Shots with the divertor septum present are compared with an identical (n) over bar (e) scan, run with the MkII GB septum replacement plate divertor at 2.5 MA/2.7 T and 2.5 MA/2.6 T. The results from this investigation indicate that removal of the septum may have lowered the (n) over tilde (e) `turning point' for P-th.
KW - spherical tokamaks
KW - boundary layer effects
KW - plasma-material interactions
KW - plasma devices
U2 - 10.1088/0741-3335/48/4/001
DO - 10.1088/0741-3335/48/4/001
M3 - Article
VL - 48
SP - 479
EP - 488
JO - Plasma Physics and Controlled Fusion
T2 - Plasma Physics and Controlled Fusion
JF - Plasma Physics and Controlled Fusion
SN - 0741-3335
IS - 4
ER -