Nondimensional transport scaling in the Tokamak Fusion Test Reactor: Is tokamak transport Bohm or gyro-Bohm?

F. W. Perkins; Cris W. Barnes; D. W. Johnson; S. D. Scott; M. C. Zarnstorff; M. G. Bell; R. E. Bell; C. E. Bush; B. Grek; K. W. Hill; D. K. Mansfield; H. Park; A. T. Ramsey; J. Schivell; B. C. Stratton; E. Synakowski

doi:10.1063/1.860534

Nondimensional transport scaling in the Tokamak Fusion Test Reactor: Is tokamak transport Bohm or gyro-Bohm?

F. W. Perkins, Cris W. Barnes, D. W. Johnson, S. D. Scott, M. C. Zarnstorff, M. G. Bell, R. E. Bell, C. E. Bush, B. Grek, K. W. Hill, D. K. Mansfield, H. Park, A. T. Ramsey, J. Schivell, B. C. Stratton, E. Synakowski

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Abstract

General plasma physics principles state that power flow Q(r) through a magnetic surface in a tokamak should scale as Q(r) = {32π²Rr ³T_e²c n_ea/[eB(a²-r ²)²]} F(ρ*,β,v*,r/a,q,s,r/R,...) where the arguments of F are local, nondimensional plasma parameters and nondimensional gradients. This paper reports an experimental determination of how F varies with normalized gyroradius ρ* ≡ (2T _eM_i)^1/2c/eBa and collisionality v* ≡ (R/r)^3/2qRv_e(m_e/ 2T_e) ^1/2 for discharges prepared so that other nondimensional parameters remain close to constant. Tokamak Fusion Test Reactor (TFTR) [D. M. Meade et al., in Plasma Physics and Controlled Nuclear Fusion Research, 1990, Proceedings of the 13th International Conference, Washington (International Atomic Energy Agency, Vienna, 1991), Vol. 1, p. 9] L-mode data show F to be independent of ρ* and numerically small, corresponding to Bohm scaling with a small multiplicative constant. By contrast, most theories predict gyro-Bohm scaling: F ∝ ρ*. Bohm scaling implies that the largest scale size for microinstability turbulence depends on machine size. Analysis of a collisionality scan finds Bohm-normalized power flow to be independent of collisionality. Implications for future theory, experiment, and reactor extrapolations are discussed.

Original language	English (US)
Pages (from-to)	477-498
Number of pages	22
Journal	Physics of Fluids B
Volume	5
Issue number	2
DOIs	https://doi.org/10.1063/1.860534
State	Published - 1993

All Science Journal Classification (ASJC) codes

Computational Mechanics
Condensed Matter Physics
Mechanics of Materials
General Physics and Astronomy
Fluid Flow and Transfer Processes

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Perkins, F. W., Barnes, C. W., Johnson, D. W., Scott, S. D., Zarnstorff, M. C., Bell, M. G., Bell, R. E., Bush, C. E., Grek, B., Hill, K. W., Mansfield, D. K., Park, H., Ramsey, A. T., Schivell, J., Stratton, B. C., & Synakowski, E. (1993). Nondimensional transport scaling in the Tokamak Fusion Test Reactor: Is tokamak transport Bohm or gyro-Bohm? Physics of Fluids B, 5(2), 477-498. https://doi.org/10.1063/1.860534

@article{6eb7806e770f47a4b33ec123457acb87,

title = "Nondimensional transport scaling in the Tokamak Fusion Test Reactor: Is tokamak transport Bohm or gyro-Bohm?",

abstract = "General plasma physics principles state that power flow Q(r) through a magnetic surface in a tokamak should scale as Q(r) = \{32π2Rr 3Te2c nea/[eB(a2-r 2)2]\} F(ρ*,β,v*,r/a,q,s,r/R,...) where the arguments of F are local, nondimensional plasma parameters and nondimensional gradients. This paper reports an experimental determination of how F varies with normalized gyroradius ρ* ≡ (2T eMi)1/2c/eBa and collisionality v* ≡ (R/r)3/2qRve(me/ 2Te) 1/2 for discharges prepared so that other nondimensional parameters remain close to constant. Tokamak Fusion Test Reactor (TFTR) [D. M. Meade et al., in Plasma Physics and Controlled Nuclear Fusion Research, 1990, Proceedings of the 13th International Conference, Washington (International Atomic Energy Agency, Vienna, 1991), Vol. 1, p. 9] L-mode data show F to be independent of ρ* and numerically small, corresponding to Bohm scaling with a small multiplicative constant. By contrast, most theories predict gyro-Bohm scaling: F ∝ ρ*. Bohm scaling implies that the largest scale size for microinstability turbulence depends on machine size. Analysis of a collisionality scan finds Bohm-normalized power flow to be independent of collisionality. Implications for future theory, experiment, and reactor extrapolations are discussed.",

author = "Perkins, \{F. W.\} and Barnes, \{Cris W.\} and Johnson, \{D. W.\} and Scott, \{S. D.\} and Zarnstorff, \{M. C.\} and Bell, \{M. G.\} and Bell, \{R. E.\} and Bush, \{C. E.\} and B. Grek and Hill, \{K. W.\} and Mansfield, \{D. K.\} and H. Park and Ramsey, \{A. T.\} and J. Schivell and Stratton, \{B. C.\} and E. Synakowski",

year = "1993",

doi = "10.1063/1.860534",

language = "English (US)",

volume = "5",

pages = "477--498",

journal = "Physics of Fluids B",

issn = "0899-8221",

publisher = "American Institute of Physics",

number = "2",

}

Perkins, FW, Barnes, CW, Johnson, DW, Scott, SD, Zarnstorff, MC, Bell, MG, Bell, RE, Bush, CE, Grek, B, Hill, KW, Mansfield, DK, Park, H, Ramsey, AT, Schivell, J, Stratton, BC & Synakowski, E 1993, 'Nondimensional transport scaling in the Tokamak Fusion Test Reactor: Is tokamak transport Bohm or gyro-Bohm?', Physics of Fluids B, vol. 5, no. 2, pp. 477-498. https://doi.org/10.1063/1.860534

TY - JOUR

T1 - Nondimensional transport scaling in the Tokamak Fusion Test Reactor

T2 - Is tokamak transport Bohm or gyro-Bohm?

AU - Perkins, F. W.

AU - Barnes, Cris W.

AU - Johnson, D. W.

AU - Scott, S. D.

AU - Zarnstorff, M. C.

AU - Bell, M. G.

AU - Bell, R. E.

AU - Bush, C. E.

AU - Grek, B.

AU - Hill, K. W.

AU - Mansfield, D. K.

AU - Park, H.

AU - Ramsey, A. T.

AU - Schivell, J.

AU - Stratton, B. C.

AU - Synakowski, E.

PY - 1993

Y1 - 1993

N2 - General plasma physics principles state that power flow Q(r) through a magnetic surface in a tokamak should scale as Q(r) = {32π2Rr 3Te2c nea/[eB(a2-r 2)2]} F(ρ*,β,v*,r/a,q,s,r/R,...) where the arguments of F are local, nondimensional plasma parameters and nondimensional gradients. This paper reports an experimental determination of how F varies with normalized gyroradius ρ* ≡ (2T eMi)1/2c/eBa and collisionality v* ≡ (R/r)3/2qRve(me/ 2Te) 1/2 for discharges prepared so that other nondimensional parameters remain close to constant. Tokamak Fusion Test Reactor (TFTR) [D. M. Meade et al., in Plasma Physics and Controlled Nuclear Fusion Research, 1990, Proceedings of the 13th International Conference, Washington (International Atomic Energy Agency, Vienna, 1991), Vol. 1, p. 9] L-mode data show F to be independent of ρ* and numerically small, corresponding to Bohm scaling with a small multiplicative constant. By contrast, most theories predict gyro-Bohm scaling: F ∝ ρ*. Bohm scaling implies that the largest scale size for microinstability turbulence depends on machine size. Analysis of a collisionality scan finds Bohm-normalized power flow to be independent of collisionality. Implications for future theory, experiment, and reactor extrapolations are discussed.

AB - General plasma physics principles state that power flow Q(r) through a magnetic surface in a tokamak should scale as Q(r) = {32π2Rr 3Te2c nea/[eB(a2-r 2)2]} F(ρ*,β,v*,r/a,q,s,r/R,...) where the arguments of F are local, nondimensional plasma parameters and nondimensional gradients. This paper reports an experimental determination of how F varies with normalized gyroradius ρ* ≡ (2T eMi)1/2c/eBa and collisionality v* ≡ (R/r)3/2qRve(me/ 2Te) 1/2 for discharges prepared so that other nondimensional parameters remain close to constant. Tokamak Fusion Test Reactor (TFTR) [D. M. Meade et al., in Plasma Physics and Controlled Nuclear Fusion Research, 1990, Proceedings of the 13th International Conference, Washington (International Atomic Energy Agency, Vienna, 1991), Vol. 1, p. 9] L-mode data show F to be independent of ρ* and numerically small, corresponding to Bohm scaling with a small multiplicative constant. By contrast, most theories predict gyro-Bohm scaling: F ∝ ρ*. Bohm scaling implies that the largest scale size for microinstability turbulence depends on machine size. Analysis of a collisionality scan finds Bohm-normalized power flow to be independent of collisionality. Implications for future theory, experiment, and reactor extrapolations are discussed.

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SN - 0899-8221

VL - 5

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EP - 498

JO - Physics of Fluids B

JF - Physics of Fluids B

IS - 2

ER -

Nondimensional transport scaling in the Tokamak Fusion Test Reactor: Is tokamak transport Bohm or gyro-Bohm?

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