Coupling between JET pedestal ne-Te and outer target plate recycling

K. McCormick; G. Maddison; C. Giroud; M. Beurskens; A. Boboc; S. Brezinsek; T. Eich; W. Fundamenski; S. Jachmich; D. Moulton; M. Stamp; H. Thomsen

doi:10.1016/j.jnucmat.2010.12.036

Coupling between JET pedestal n_e-T_e and outer target plate recycling

K. McCormick, G. Maddison, C. Giroud, M. Beurskens, A. Boboc, S. Brezinsek, T. Eich, W. Fundamenski, S. Jachmich, D. Moulton, M. Stamp, H. Thomsen

Laboratory for Plasma Physics

Research output: Contribution to journal › Article › peer-review

Abstract

Systematic scans using D₂ gas puffing and impurity-seeding (Ne, N₂) have been carried out on ELMy-H and Advanced-Tokamak-like discharges to study power deposition amelioration at the divertor target plates in preparation for the JET ITER-Like Wall (ILW). Hereby it has been discovered that the recycling ion fluxes I_div to the outer target plate exhibit a clear connection to pedestal n_e and T_e, whereby the D_α photon flux Φ_Dα from the outer divertor serves here as an approximate measure of I_div. Φ _Dα can be expressed as (n_e/T_e) ^β with β = 2.5/3 depending on the scenario (EH/AT). This coupling between SOL and pedestal across the edge transport barrier (ETB) is associated with a close connection between n_e and T_e in the ETB over the entire range of operational parameters, with the slope of log T_e vs. log n_e being ∼0.9/1.24 for ET/AT scenarios, respectively.

Original language	English
Pages (from-to)	S421-S424
Journal	Journal of Nuclear Materials
Volume	415
Issue number	1 SUPPL
DOIs	https://doi.org/10.1016/j.jnucmat.2010.12.036
Publication status	Published - 1 Aug 2011

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title = "Coupling between JET pedestal ne-Te and outer target plate recycling",

abstract = "Systematic scans using D2 gas puffing and impurity-seeding (Ne, N2) have been carried out on ELMy-H and Advanced-Tokamak-like discharges to study power deposition amelioration at the divertor target plates in preparation for the JET ITER-Like Wall (ILW). Hereby it has been discovered that the recycling ion fluxes Idiv to the outer target plate exhibit a clear connection to pedestal ne and Te, whereby the Dα photon flux ΦDα from the outer divertor serves here as an approximate measure of Idiv. Φ Dα can be expressed as (ne/Te) β with β = 2.5/3 depending on the scenario (EH/AT). This coupling between SOL and pedestal across the edge transport barrier (ETB) is associated with a close connection between ne and Te in the ETB over the entire range of operational parameters, with the slope of log Te vs. log ne being ∼0.9/1.24 for ET/AT scenarios, respectively.",

author = "K. McCormick and G. Maddison and C. Giroud and M. Beurskens and A. Boboc and S. Brezinsek and T. Eich and W. Fundamenski and S. Jachmich and D. Moulton and M. Stamp and H. Thomsen",

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doi = "10.1016/j.jnucmat.2010.12.036",

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AU - McCormick, K.

AU - Maddison, G.

AU - Giroud, C.

AU - Beurskens, M.

AU - Boboc, A.

AU - Brezinsek, S.

AU - Eich, T.

AU - Fundamenski, W.

AU - Jachmich, S.

AU - Moulton, D.

AU - Stamp, M.

AU - Thomsen, H.

PY - 2011/8/1

Y1 - 2011/8/1

N2 - Systematic scans using D2 gas puffing and impurity-seeding (Ne, N2) have been carried out on ELMy-H and Advanced-Tokamak-like discharges to study power deposition amelioration at the divertor target plates in preparation for the JET ITER-Like Wall (ILW). Hereby it has been discovered that the recycling ion fluxes Idiv to the outer target plate exhibit a clear connection to pedestal ne and Te, whereby the Dα photon flux ΦDα from the outer divertor serves here as an approximate measure of Idiv. Φ Dα can be expressed as (ne/Te) β with β = 2.5/3 depending on the scenario (EH/AT). This coupling between SOL and pedestal across the edge transport barrier (ETB) is associated with a close connection between ne and Te in the ETB over the entire range of operational parameters, with the slope of log Te vs. log ne being ∼0.9/1.24 for ET/AT scenarios, respectively.

AB - Systematic scans using D2 gas puffing and impurity-seeding (Ne, N2) have been carried out on ELMy-H and Advanced-Tokamak-like discharges to study power deposition amelioration at the divertor target plates in preparation for the JET ITER-Like Wall (ILW). Hereby it has been discovered that the recycling ion fluxes Idiv to the outer target plate exhibit a clear connection to pedestal ne and Te, whereby the Dα photon flux ΦDα from the outer divertor serves here as an approximate measure of Idiv. Φ Dα can be expressed as (ne/Te) β with β = 2.5/3 depending on the scenario (EH/AT). This coupling between SOL and pedestal across the edge transport barrier (ETB) is associated with a close connection between ne and Te in the ETB over the entire range of operational parameters, with the slope of log Te vs. log ne being ∼0.9/1.24 for ET/AT scenarios, respectively.

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SP - S421-S424

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Coupling between JET pedestal n_e-T_e and outer target plate recycling

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