Effect of N2, Ne and Ar seeding on Alcator C-Mod H-mode confinement

M.L. Reinke; J.W. Hughes; A. Loarte; D. Brunner; I.H. Hutchinson; B. LaBombard; J. Payne; J.L. Terry

doi:10.1016/j.jnucmat.2010.10.055

Effect of N2, Ne and Ar seeding on Alcator C-Mod H-mode confinement

M.L. Reinke, J.W. Hughes, A. Loarte, D. Brunner, I.H. Hutchinson, B. LaBombard, J. Payne, J.L. Terry

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

Abstract

The mitigation of divertor heat fluxes is an active topic of investigation on existing tokamaks. One approach uses radiation, both inside and outside the last closed flux surface (LCFS), to convert plasma thermal energy, usually directed towards dedicated plasma facing components, to soft X-ray and ultraviolet radiation, spread over a much larger surface area. Recent enhanced D-α H-mode experiments on Alcator C-Mod varied the ICRF input power and radiative power losses via impurity seeding to demonstrate that normalized energy confinement depends strongly on the difference between input power and the radiated power inside the LCFS. These investigations also show that when seeded with either Ne or N, a factor of two and higher reduction in outer divertor heat flux is achieved while maintaining H ∼ 1.0. Conversely, when seeding with Ar, confinement is limited to H ∼ 0.8 for a similar level of exhaust power.

Original language	English
Pages (from-to)	S340-S344
Number of pages	5
Journal	Journal of Nuclear Materials
Volume	415
Issue number	1 SUPPL.
Early online date	5 Nov 2010
DOIs	https://doi.org/10.1016/j.jnucmat.2010.10.055
Publication status	Published - 1 Aug 2011

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10.1016/j.jnucmat.2010.10.055

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title = "Effect of N2, Ne and Ar seeding on Alcator C-Mod H-mode confinement",

abstract = "The mitigation of divertor heat fluxes is an active topic of investigation on existing tokamaks. One approach uses radiation, both inside and outside the last closed flux surface (LCFS), to convert plasma thermal energy, usually directed towards dedicated plasma facing components, to soft X-ray and ultraviolet radiation, spread over a much larger surface area. Recent enhanced D-α H-mode experiments on Alcator C-Mod varied the ICRF input power and radiative power losses via impurity seeding to demonstrate that normalized energy confinement depends strongly on the difference between input power and the radiated power inside the LCFS. These investigations also show that when seeded with either Ne or N, a factor of two and higher reduction in outer divertor heat flux is achieved while maintaining H ∼ 1.0. Conversely, when seeding with Ar, confinement is limited to H ∼ 0.8 for a similar level of exhaust power.",

author = "M.L. Reinke and J.W. Hughes and A. Loarte and D. Brunner and I.H. Hutchinson and B. LaBombard and J. Payne and J.L. Terry",

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AU - Reinke, M.L.

AU - Hughes, J.W.

AU - Loarte, A.

AU - Brunner, D.

AU - Hutchinson, I.H.

AU - LaBombard, B.

AU - Payne, J.

AU - Terry, J.L.

PY - 2011/8/1

Y1 - 2011/8/1

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AB - The mitigation of divertor heat fluxes is an active topic of investigation on existing tokamaks. One approach uses radiation, both inside and outside the last closed flux surface (LCFS), to convert plasma thermal energy, usually directed towards dedicated plasma facing components, to soft X-ray and ultraviolet radiation, spread over a much larger surface area. Recent enhanced D-α H-mode experiments on Alcator C-Mod varied the ICRF input power and radiative power losses via impurity seeding to demonstrate that normalized energy confinement depends strongly on the difference between input power and the radiated power inside the LCFS. These investigations also show that when seeded with either Ne or N, a factor of two and higher reduction in outer divertor heat flux is achieved while maintaining H ∼ 1.0. Conversely, when seeding with Ar, confinement is limited to H ∼ 0.8 for a similar level of exhaust power.

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Effect of N2, Ne and Ar seeding on Alcator C-Mod H-mode confinement

Abstract

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