Zero-Turbulence Manifold in a Toroidal Plasma
Sheared toroidal flows can cause bifurcations to zero-turbulent-transport states in tokamak plasmas. The maximum temperature gradients that can be reached are limited by subcritical turbulence driven by the parallel velocity gradient. Here it is shown that q/ϵ (magnetic field pitch/inverse aspect ra...
| Main Authors: | , , , , , , |
|---|---|
| Other Authors: | |
| Format: | Article |
| Language: | en_US |
| Published: |
American Physical Society
2013
|
| Online Access: | http://hdl.handle.net/1721.1/77169 https://orcid.org/0000-0001-9621-7404 |
| _version_ | 1811072465528422400 |
|---|---|
| author | Highcock, E. G. Schekochihin, A. A. Cowley, S. C. Barnes, Michael Parra Diaz, Felix Ignacio Roach, C. M. Dorland, W. |
| author2 | Massachusetts Institute of Technology. Department of Nuclear Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Highcock, E. G. Schekochihin, A. A. Cowley, S. C. Barnes, Michael Parra Diaz, Felix Ignacio Roach, C. M. Dorland, W. |
| author_sort | Highcock, E. G. |
| collection | MIT |
| description | Sheared toroidal flows can cause bifurcations to zero-turbulent-transport states in tokamak plasmas. The maximum temperature gradients that can be reached are limited by subcritical turbulence driven by the parallel velocity gradient. Here it is shown that q/ϵ (magnetic field pitch/inverse aspect ratio) is a critical control parameter for sheared tokamak turbulence. By reducing q/ϵ, far higher temperature gradients can be achieved without triggering turbulence, in some instances comparable to those found experimentally in transport barriers. The zero-turbulence manifold is mapped out, in the zero-magnetic-shear limit, over the parameter space (γ[subscript E], q/ϵ, R/L[subscript T]), where γ[subscript E] is the perpendicular flow shear and R/L[subscript T] is the normalized inverse temperature gradient scale. The extent to which it can be constructed from linear theory is discussed. |
| first_indexed | 2024-09-23T09:06:23Z |
| format | Article |
| id | mit-1721.1/77169 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T09:06:23Z |
| publishDate | 2013 |
| publisher | American Physical Society |
| record_format | dspace |
| spelling | mit-1721.1/771692022-09-30T13:27:37Z Zero-Turbulence Manifold in a Toroidal Plasma Highcock, E. G. Schekochihin, A. A. Cowley, S. C. Barnes, Michael Parra Diaz, Felix Ignacio Roach, C. M. Dorland, W. Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Massachusetts Institute of Technology. Plasma Science and Fusion Center Barnes, Michael Parra Diaz, Felix Ignacio Sheared toroidal flows can cause bifurcations to zero-turbulent-transport states in tokamak plasmas. The maximum temperature gradients that can be reached are limited by subcritical turbulence driven by the parallel velocity gradient. Here it is shown that q/ϵ (magnetic field pitch/inverse aspect ratio) is a critical control parameter for sheared tokamak turbulence. By reducing q/ϵ, far higher temperature gradients can be achieved without triggering turbulence, in some instances comparable to those found experimentally in transport barriers. The zero-turbulence manifold is mapped out, in the zero-magnetic-shear limit, over the parameter space (γ[subscript E], q/ϵ, R/L[subscript T]), where γ[subscript E] is the perpendicular flow shear and R/L[subscript T] is the normalized inverse temperature gradient scale. The extent to which it can be constructed from linear theory is discussed. 2013-02-21T14:06:11Z 2013-02-21T14:06:11Z 2012-12 2012-11 Article http://purl.org/eprint/type/JournalArticle 0031-9007 1079-7114 http://hdl.handle.net/1721.1/77169 Highcock, E. G. et al. “Zero-Turbulence Manifold in a Toroidal Plasma.” Physical Review Letters 109.26 (2012): n. pag. CrossRef. © 2012 American Physical Society https://orcid.org/0000-0001-9621-7404 en_US http://dx.doi.org/10.1103/PhysRevLett.109.265001 Physical Review Letters Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf American Physical Society APS |
| spellingShingle | Highcock, E. G. Schekochihin, A. A. Cowley, S. C. Barnes, Michael Parra Diaz, Felix Ignacio Roach, C. M. Dorland, W. Zero-Turbulence Manifold in a Toroidal Plasma |
| title | Zero-Turbulence Manifold in a Toroidal Plasma |
| title_full | Zero-Turbulence Manifold in a Toroidal Plasma |
| title_fullStr | Zero-Turbulence Manifold in a Toroidal Plasma |
| title_full_unstemmed | Zero-Turbulence Manifold in a Toroidal Plasma |
| title_short | Zero-Turbulence Manifold in a Toroidal Plasma |
| title_sort | zero turbulence manifold in a toroidal plasma |
| url | http://hdl.handle.net/1721.1/77169 https://orcid.org/0000-0001-9621-7404 |
| work_keys_str_mv | AT highcockeg zeroturbulencemanifoldinatoroidalplasma AT schekochihinaa zeroturbulencemanifoldinatoroidalplasma AT cowleysc zeroturbulencemanifoldinatoroidalplasma AT barnesmichael zeroturbulencemanifoldinatoroidalplasma AT parradiazfelixignacio zeroturbulencemanifoldinatoroidalplasma AT roachcm zeroturbulencemanifoldinatoroidalplasma AT dorlandw zeroturbulencemanifoldinatoroidalplasma |