View in EDS

Quiescent H-mode operation using torque from non-axisymmetric, non-resonant magnetic fields.

Saved in:
Bibliographic Details
Title: Quiescent H-mode operation using torque from non-axisymmetric, non-resonant magnetic fields.
Authors: Burrell, K. H.1 burrell@fusion.gat.com, Garofalo, A. M.1, Solomon, W. M.2, Fenstermacher, M. E.3, Orlov, D. M.4, Osborne, T. H.1, Park, J.-K.2, Snyder, P. B.1
Source: Nuclear Fusion. 2013, Vol. 53 Issue 7, p1-10. 10p.
Subjects: Quiescent plasmas, Symmetry (Physics), Magnetic fields, International Thermonuclear Experimental Reactor (Project), Magnetic torque, Plasma beam injection heating
Abstract: Quiescent H-mode (QH-mode) sustained by magnetic torque from non-axisymmetric magnetic fields is a promising operating mode for future burning plasmas including ITER. Using magnetic torque from n = 3 fields to replace counter-Ip torque from neutral beam injection, we have achieved long duration, counter-rotating QH-mode operation with neutral beam injection (NBI) torque ranging continuously from counter-Ip up to co-Ip values of about 1 Nm. This co-Ip torque is about 3 times the scaled torque that ITER will have. This range also includes operation at zero net NBI torque, applicable to rf wave heated plasmas. These n = 3 fields have been created using coils either inside or, most recently, outside the toroidal coils. Experiments utilized an ITER-relevant lower single-null plasma shape and were done with ITER-relevant values vped* ~ 0.08,βTped;~ 1%and βN = 2. Discharges have confinement quality H98y2 = 1.3, exceeding the value required for ITER. Initial work with low q95 = 3.4 QH-mode plasmas transiently reached fusion gain values of G = H89/q95² = 0.4, which is the desired value for ITER; the limits on G have not yet been established. This paper also includes the most recent results on QH-mode plasmas run without n = 3 fields and with co-Ip NBI; these shots exhibit co-Ip plasma rotation and require NBI torque ≥2 N m. The QH-mode work to date has made significant contact with theory. The importance of edge rotational shear is consistent with peeling-ballooning mode theory. We have seen qualitative and quantitative agreement with the predicted torque from neoclassical toroidal viscosity. [ABSTRACT FROM AUTHOR]
Copyright of Nuclear Fusion is the property of IOP Publishing and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
Database: Engineering Source
Description
Abstract:Quiescent H-mode (QH-mode) sustained by magnetic torque from non-axisymmetric magnetic fields is a promising operating mode for future burning plasmas including ITER. Using magnetic torque from n = 3 fields to replace counter-Ip torque from neutral beam injection, we have achieved long duration, counter-rotating QH-mode operation with neutral beam injection (NBI) torque ranging continuously from counter-Ip up to co-Ip values of about 1 Nm. This co-Ip torque is about 3 times the scaled torque that ITER will have. This range also includes operation at zero net NBI torque, applicable to rf wave heated plasmas. These n = 3 fields have been created using coils either inside or, most recently, outside the toroidal coils. Experiments utilized an ITER-relevant lower single-null plasma shape and were done with ITER-relevant values vped* ~ 0.08,&#946Tped;~ 1%and βN = 2. Discharges have confinement quality H98y2 = 1.3, exceeding the value required for ITER. Initial work with low q95 = 3.4 QH-mode plasmas transiently reached fusion gain values of G = H89/q95² = 0.4, which is the desired value for ITER; the limits on G have not yet been established. This paper also includes the most recent results on QH-mode plasmas run without n = 3 fields and with co-Ip NBI; these shots exhibit co-Ip plasma rotation and require NBI torque ≥2 N m. The QH-mode work to date has made significant contact with theory. The importance of edge rotational shear is consistent with peeling-ballooning mode theory. We have seen qualitative and quantitative agreement with the predicted torque from neoclassical toroidal viscosity. [ABSTRACT FROM AUTHOR]
ISSN:00295515
DOI:10.1088/0029-5515/53/7/073038