National Technical Reports Library

The National Technical Information Service acquires, indexes, abstracts, and archives the largest collection of U.S. government-sponsored technical reports in existence. The NTRL offers online, free and open access to these authenticated government technical reports. Technical reports and documents in its repository may be available online for free either from the issuing federal agency, the U.S. Government Publishing Office’s Federal Digital System website, or through search engines.

Details

Electric Potential Cells at the Diverted Tokamak Separatrix.

DE2004825651

Publication Date	2000
Personal Author	Schaffer, M. J.; Porter, G. D.; Boedo, J. A.
Page Count	22
Abstract	OAK-B135 Two-dimensional measurements by probes and Thomson scattering reveal unanticipated electric potential and electron pressure (P(sub e)) maxima near the divertor X-point in L-mode plasmas in the DIII-D tokamak. The potential hill ((approx) 50 V) drives E x B circulation (potential cell) of particles, energy and toroidal momentum around the X-point and in and out across the magnetic separatrix. modeling by the UEDGE two-dimensional edge transport code with plasma drifts shows similar X-point potential and pressure hills. The code predicts additional drift-driven nonuniformity poloidally around the separatrix. Potential cells in UEDGE arise from parallel (to B) viscous stress acting on the Pfirsch-Schlueter ion return flow of the (del)B drift. These experimental and theoretical results demonstrate that the boundary layer just inside the separatrix of low power tokamak plasmas can be far from poloidal uniformity. They speculate that separatrix potential cells might be a major feature of L-mode edge transport and their suppression an important feature of H-mode.
Keywords	Electric potential Tokamak devices Plasmas Meetings Measurements Probes (Measuring devices) Thompson scattering Doublet 3 devices Tokamak separatrix Doublet 3 device (DIII-D) UEDGE computer program
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; California Univ., San Diego, La Jolla.; Toronto Univ. (Ontario).; Department of Energy, Washington, DC.; Sandia National Labs., Albuquerque, NM.
Supplemental Notes	Prepared in cooperation with California Univ., San Diego, La Jolla., Toronto Univ. (Ontario). and Sandia National Labs., Albuquerque, NM. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200512

Electric Potential Cells at the Diverted Tokamak Separatrix.

Electric Potential Cells at the Diverted Tokamak Separatrix.
DE2004825651

Publication Date	2000
Personal Author	Schaffer, M. J.; Porter, G. D.; Boedo, J. A.
Page Count	22
Abstract	OAK-B135 Two-dimensional measurements by probes and Thomson scattering reveal unanticipated electric potential and electron pressure (P(sub e)) maxima near the divertor X-point in L-mode plasmas in the DIII-D tokamak. The potential hill ((approx) 50 V) drives E x B circulation (potential cell) of particles, energy and toroidal momentum around the X-point and in and out across the magnetic separatrix. modeling by the UEDGE two-dimensional edge transport code with plasma drifts shows similar X-point potential and pressure hills. The code predicts additional drift-driven nonuniformity poloidally around the separatrix. Potential cells in UEDGE arise from parallel (to B) viscous stress acting on the Pfirsch-Schlueter ion return flow of the (del)B drift. These experimental and theoretical results demonstrate that the boundary layer just inside the separatrix of low power tokamak plasmas can be far from poloidal uniformity. They speculate that separatrix potential cells might be a major feature of L-mode edge transport and their suppression an important feature of H-mode.
Keywords	Electric potential Tokamak devices Plasmas Meetings Measurements Probes (Measuring devices) Thompson scattering Doublet 3 devices Tokamak separatrix Doublet 3 device (DIII-D) UEDGE computer program
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Lawrence Livermore National Lab., CA.; California Univ., San Diego, La Jolla.; Toronto Univ. (Ontario).; Department of Energy, Washington, DC.; Sandia National Labs., Albuquerque, NM.
Supplemental Notes	Prepared in cooperation with California Univ., San Diego, La Jolla., Toronto Univ. (Ontario). and Sandia National Labs., Albuquerque, NM. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200512