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Adjoint optimization scheme for lower hybrid current rampup and profile control in Tokamak

Abstract

The purpose of this work is to take into account and study the effect of the electric field profiles on the Lower Hybrid (LH) current drive efficiency during transient phases such as rampup. As a complement to the full ray-tracing / Fokker Planck studies, and for the purpose of optimization studies, we developed a simplified 1-D model based on the adjoint Karney-Fisch numerical results. This approach allows us to estimate the LH power deposition profile which would be required for ramping the current with prescribed rate, total current density profile (q-profile) and surface loop voltage. For rampup optimization studies, we can therefore scan the whole parameter space and eliminate a posteriori those scenarios which correspond to unrealistic deposition profiles. We thus obtain the time evolution of the LH power, minor radius of the plasma, volt-second consumption and total energy dissipated. Optimization can thus be performed with respect to any of those criteria. This scheme is illustrated by some numerical simulations performed with TORE-SUPRA and NET/ITER parameters. We conclude with a derivation of a simple and general scaling law for the flux consumption during the rampup phase.
Authors:
Litaudon, X; Moreau, D; Bizarro, J P; Hoang, G T; Kupfer, K; Peysson, Y; [1]  Fuchs, V; [2]  Shkarofsky, I P; [3]  Bonoli, P [4] 
  1. Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 -Saint- Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee
  2. Centre Canadien de Fusion Magnetique, Varennes, PW (Canada)
  3. MPB Technologies, Inc., Ste. Anne de Bellevue, PQ (Canada)
  4. Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center
Publication Date:
Dec 01, 1992
Product Type:
Technical Report
Report Number:
EUR-CEA-FC-1472
Reference Number:
SCA: 700350; PA: AIX-25:016575; EDB-94:033858; ERA-19:011059; SN: 94001146564
Resource Relation:
Other Information: PBD: Dec 1992
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; TOKAMAK DEVICES; LOWER HYBRID CURRENT DRIVE; CURRENT DENSITY; ELECTRIC FIELDS; ENERGY DEPOSITION; ONE-DIMENSIONAL CALCULATIONS; OPTIMIZATION; TRANSIENTS; 700350; PLASMA PRODUCTION, HEATING, CURRENT DRIVE, AND INTERACTIONS
OSTI ID:
10123456
Research Organizations:
Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee
Country of Origin:
France
Language:
English
Other Identifying Numbers:
Other: ON: TI94612611; CNN: Contract NET/90-251; TRN: FR9302751016575
Availability:
OSTI; NTIS (US Sales Only); INIS
Submitting Site:
FRN
Size:
33 p.
Announcement Date:
Jul 04, 2005

Citation Formats

Litaudon, X, Moreau, D, Bizarro, J P, Hoang, G T, Kupfer, K, Peysson, Y, Fuchs, V, Shkarofsky, I P, and Bonoli, P. Adjoint optimization scheme for lower hybrid current rampup and profile control in Tokamak. France: N. p., 1992. Web.
Litaudon, X, Moreau, D, Bizarro, J P, Hoang, G T, Kupfer, K, Peysson, Y, Fuchs, V, Shkarofsky, I P, & Bonoli, P. Adjoint optimization scheme for lower hybrid current rampup and profile control in Tokamak. France.
Litaudon, X, Moreau, D, Bizarro, J P, Hoang, G T, Kupfer, K, Peysson, Y, Fuchs, V, Shkarofsky, I P, and Bonoli, P. 1992. "Adjoint optimization scheme for lower hybrid current rampup and profile control in Tokamak." France.
@misc{etde_10123456,
title = {Adjoint optimization scheme for lower hybrid current rampup and profile control in Tokamak}
author = {Litaudon, X, Moreau, D, Bizarro, J P, Hoang, G T, Kupfer, K, Peysson, Y, Fuchs, V, Shkarofsky, I P, and Bonoli, P}
abstractNote = {The purpose of this work is to take into account and study the effect of the electric field profiles on the Lower Hybrid (LH) current drive efficiency during transient phases such as rampup. As a complement to the full ray-tracing / Fokker Planck studies, and for the purpose of optimization studies, we developed a simplified 1-D model based on the adjoint Karney-Fisch numerical results. This approach allows us to estimate the LH power deposition profile which would be required for ramping the current with prescribed rate, total current density profile (q-profile) and surface loop voltage. For rampup optimization studies, we can therefore scan the whole parameter space and eliminate a posteriori those scenarios which correspond to unrealistic deposition profiles. We thus obtain the time evolution of the LH power, minor radius of the plasma, volt-second consumption and total energy dissipated. Optimization can thus be performed with respect to any of those criteria. This scheme is illustrated by some numerical simulations performed with TORE-SUPRA and NET/ITER parameters. We conclude with a derivation of a simple and general scaling law for the flux consumption during the rampup phase.}
place = {France}
year = {1992}
month = {Dec}
}