## Abstract

Neoclassical transport in the banana regime has been analyzed with the DKES (Drift Kinetic Equation Solver) code for the Large Helical Device (LHD). It is found that in a 1/v regime, diffusion coefficients change by one order of magnitude for various configurations of LHD (-0.2 m {<=} {Delta} {<=} 0 m, 0% {<=} Bq {<=} 200%, -0.1 {<=} {alpha} {<=} 0.1), depending on the structure of the helical magnetic ripple. The neoclassical transport calculated with the DKES code is quantitatively, in good agreement with multi-helicity theory formulated by Shaing and Hokin. Incorporating the multi-helicity effect into the diffusion coefficient, we have proposed an interpolation formula between the 1/v and v regimes. When the ion temperature is increased at a fixed density of n = 10{sup 20} m{sup -3}, the ions undergo a transition from 1/v neoclassical transport to the v regime when their temperature T{sub i} becomes > 3 keV with radial electric potential e{phi} comparable to the ion temperature (e{phi}/T{sub i} {approx_equal} 1). For the optimized configuration ({Delta} = -0.2 m, Bq = 100%), the ion thermal diffusivity {chi}{sub i} has a maximum value of {chi}{sub i} {approx_equal} 3.5 m{sup 2}/s at a minor radius of r/a {approx_equal} 0.5.
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## Citation Formats

Ogawa, Y, Amano, T, Nakajima, N, Ohyabu, Y, Yamazaki, K, Hirshman, S P, Van Rij, W I, and Shaing, K C.
Neoclassical transport analysis in the banana regime on Large Helical Device (LHD) with the DKES code.
Japan: N. p.,
1991.
Web.

Ogawa, Y, Amano, T, Nakajima, N, Ohyabu, Y, Yamazaki, K, Hirshman, S P, Van Rij, W I, & Shaing, K C.
Neoclassical transport analysis in the banana regime on Large Helical Device (LHD) with the DKES code.
Japan.

Ogawa, Y, Amano, T, Nakajima, N, Ohyabu, Y, Yamazaki, K, Hirshman, S P, Van Rij, W I, and Shaing, K C.
1991.
"Neoclassical transport analysis in the banana regime on Large Helical Device (LHD) with the DKES code."
Japan.

@misc{etde_10117080,

title = {Neoclassical transport analysis in the banana regime on Large Helical Device (LHD) with the DKES code}

author = {Ogawa, Y, Amano, T, Nakajima, N, Ohyabu, Y, Yamazaki, K, Hirshman, S P, Van Rij, W I, and Shaing, K C}

abstractNote = {Neoclassical transport in the banana regime has been analyzed with the DKES (Drift Kinetic Equation Solver) code for the Large Helical Device (LHD). It is found that in a 1/v regime, diffusion coefficients change by one order of magnitude for various configurations of LHD (-0.2 m {<=} {Delta} {<=} 0 m, 0% {<=} Bq {<=} 200%, -0.1 {<=} {alpha} {<=} 0.1), depending on the structure of the helical magnetic ripple. The neoclassical transport calculated with the DKES code is quantitatively, in good agreement with multi-helicity theory formulated by Shaing and Hokin. Incorporating the multi-helicity effect into the diffusion coefficient, we have proposed an interpolation formula between the 1/v and v regimes. When the ion temperature is increased at a fixed density of n = 10{sup 20} m{sup -3}, the ions undergo a transition from 1/v neoclassical transport to the v regime when their temperature T{sub i} becomes > 3 keV with radial electric potential e{phi} comparable to the ion temperature (e{phi}/T{sub i} {approx_equal} 1). For the optimized configuration ({Delta} = -0.2 m, Bq = 100%), the ion thermal diffusivity {chi}{sub i} has a maximum value of {chi}{sub i} {approx_equal} 3.5 m{sup 2}/s at a minor radius of r/a {approx_equal} 0.5. The bootstrap current has been also studied, and the results have been comprehensively compared with the theory. At the collisionless limit with a moderate radial electric potential of e{phi}/T{sub i} {approx_equal} 1, the DKES calculations evaluated for various configurations of LHD have supported the theoretical formula given by Shaing and Callen. At the collision frequency between the plateau and the banana regimes, where the analytic theory is not applicable, the bootstrap current might become larger than in the collisionless limit (by a factor of about two), depending on the radial electric fields. (author).}

place = {Japan}

year = {1991}

month = {Sep}

}

title = {Neoclassical transport analysis in the banana regime on Large Helical Device (LHD) with the DKES code}

author = {Ogawa, Y, Amano, T, Nakajima, N, Ohyabu, Y, Yamazaki, K, Hirshman, S P, Van Rij, W I, and Shaing, K C}

abstractNote = {Neoclassical transport in the banana regime has been analyzed with the DKES (Drift Kinetic Equation Solver) code for the Large Helical Device (LHD). It is found that in a 1/v regime, diffusion coefficients change by one order of magnitude for various configurations of LHD (-0.2 m {<=} {Delta} {<=} 0 m, 0% {<=} Bq {<=} 200%, -0.1 {<=} {alpha} {<=} 0.1), depending on the structure of the helical magnetic ripple. The neoclassical transport calculated with the DKES code is quantitatively, in good agreement with multi-helicity theory formulated by Shaing and Hokin. Incorporating the multi-helicity effect into the diffusion coefficient, we have proposed an interpolation formula between the 1/v and v regimes. When the ion temperature is increased at a fixed density of n = 10{sup 20} m{sup -3}, the ions undergo a transition from 1/v neoclassical transport to the v regime when their temperature T{sub i} becomes > 3 keV with radial electric potential e{phi} comparable to the ion temperature (e{phi}/T{sub i} {approx_equal} 1). For the optimized configuration ({Delta} = -0.2 m, Bq = 100%), the ion thermal diffusivity {chi}{sub i} has a maximum value of {chi}{sub i} {approx_equal} 3.5 m{sup 2}/s at a minor radius of r/a {approx_equal} 0.5. The bootstrap current has been also studied, and the results have been comprehensively compared with the theory. At the collisionless limit with a moderate radial electric potential of e{phi}/T{sub i} {approx_equal} 1, the DKES calculations evaluated for various configurations of LHD have supported the theoretical formula given by Shaing and Callen. At the collision frequency between the plateau and the banana regimes, where the analytic theory is not applicable, the bootstrap current might become larger than in the collisionless limit (by a factor of about two), depending on the radial electric fields. (author).}

place = {Japan}

year = {1991}

month = {Sep}

}