Resistive n = 1 modes in reversed magnetic shear Alcator C-Mod plasmas

Y. In; J. J. Ramos; A. E. Hubbard; I. H. Hutchinson; M. Porkolab; J. Snipes; S. M. Wolfe; A. Bondeson

doi:10.1088/0029-5515/40/8/304

Resistive n = 1 modes in reversed magnetic shear Alcator C-Mod plasmas

Y. In, J. J. Ramos, A. E. Hubbard, I. H. Hutchinson, M. Porkolab, J. Snipes, S. M. Wolfe, A. Bondeson

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

12 Scopus citations

Abstract

During current rampup discharges with early auxiliary RFD heating, reversed magnetic shear profiles have been obtained on Alcator C-Mod. MHD oscillations are often observed on ECE diagnostics, as well as magnetics. Although no direct q profile measurement was available, a hollow current density profile with q_min = 2.5 was reconstructed by the EFIT program. The location of the largest electron temperature fluctuations was close to the outer q = 3 rational surface. On the basis of a resistive linear stability code (MARS), the MHD oscillations were identified as n = 1 resistive `multiple' tearing modes. Since the pressure profile was hollow and q>1 in the core, a resistive interchange mode was also predicted to be unstable at the inner q = 4 rational surface, despite the low β_N.

Original language	English (US)
Pages (from-to)	1463-1468
Number of pages	6
Journal	Nuclear Fusion
Volume	40
Issue number	8
DOIs	https://doi.org/10.1088/0029-5515/40/8/304
State	Published - Aug 2000
Externally published	Yes

All Science Journal Classification (ASJC) codes

Nuclear and High Energy Physics
Condensed Matter Physics

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Cite this

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title = "Resistive n = 1 modes in reversed magnetic shear Alcator C-Mod plasmas",

abstract = "During current rampup discharges with early auxiliary RFD heating, reversed magnetic shear profiles have been obtained on Alcator C-Mod. MHD oscillations are often observed on ECE diagnostics, as well as magnetics. Although no direct q profile measurement was available, a hollow current density profile with qmin = 2.5 was reconstructed by the EFIT program. The location of the largest electron temperature fluctuations was close to the outer q = 3 rational surface. On the basis of a resistive linear stability code (MARS), the MHD oscillations were identified as n = 1 resistive `multiple' tearing modes. Since the pressure profile was hollow and q>1 in the core, a resistive interchange mode was also predicted to be unstable at the inner q = 4 rational surface, despite the low βN.",

author = "Y. In and Ramos, \{J. J.\} and Hubbard, \{A. E.\} and Hutchinson, \{I. H.\} and M. Porkolab and J. Snipes and Wolfe, \{S. M.\} and A. Bondeson",

year = "2000",

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doi = "10.1088/0029-5515/40/8/304",

language = "English (US)",

volume = "40",

pages = "1463--1468",

journal = "Nuclear Fusion",

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TY - JOUR

T1 - Resistive n = 1 modes in reversed magnetic shear Alcator C-Mod plasmas

AU - In, Y.

AU - Ramos, J. J.

AU - Hubbard, A. E.

AU - Hutchinson, I. H.

AU - Porkolab, M.

AU - Snipes, J.

AU - Wolfe, S. M.

AU - Bondeson, A.

PY - 2000/8

Y1 - 2000/8

N2 - During current rampup discharges with early auxiliary RFD heating, reversed magnetic shear profiles have been obtained on Alcator C-Mod. MHD oscillations are often observed on ECE diagnostics, as well as magnetics. Although no direct q profile measurement was available, a hollow current density profile with qmin = 2.5 was reconstructed by the EFIT program. The location of the largest electron temperature fluctuations was close to the outer q = 3 rational surface. On the basis of a resistive linear stability code (MARS), the MHD oscillations were identified as n = 1 resistive `multiple' tearing modes. Since the pressure profile was hollow and q>1 in the core, a resistive interchange mode was also predicted to be unstable at the inner q = 4 rational surface, despite the low βN.

AB - During current rampup discharges with early auxiliary RFD heating, reversed magnetic shear profiles have been obtained on Alcator C-Mod. MHD oscillations are often observed on ECE diagnostics, as well as magnetics. Although no direct q profile measurement was available, a hollow current density profile with qmin = 2.5 was reconstructed by the EFIT program. The location of the largest electron temperature fluctuations was close to the outer q = 3 rational surface. On the basis of a resistive linear stability code (MARS), the MHD oscillations were identified as n = 1 resistive `multiple' tearing modes. Since the pressure profile was hollow and q>1 in the core, a resistive interchange mode was also predicted to be unstable at the inner q = 4 rational surface, despite the low βN.

UR - https://www.scopus.com/pages/publications/0034250682

UR - https://www.scopus.com/inward/citedby.url?scp=0034250682&partnerID=8YFLogxK

U2 - 10.1088/0029-5515/40/8/304

DO - 10.1088/0029-5515/40/8/304

M3 - Article

AN - SCOPUS:0034250682

SN - 0029-5515

VL - 40

SP - 1463

EP - 1468

JO - Nuclear Fusion

JF - Nuclear Fusion

IS - 8

ER -

Resistive n = 1 modes in reversed magnetic shear Alcator C-Mod plasmas

Abstract

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