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P. Barabaschi - One of the best experts on this subject based on the ideXlab platform.
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the jt 60sa Toroidal Field magnet design for assembly
IEEE Transactions on Applied Superconductivity, 2012Co-Authors: S Davis, D Duglue, N Hajnal, G Phillips, P. Barabaschi, Kazuki Shibanuma, Valerio TomarchioAbstract:The JT-60SA experiment will be the world's largest superconducting tokamak when it is assembled in Naka, Japan (R = 3 m, a = 1.2 m). This paper describes the approach taken to define appropriate manufacturing tolerances and metrology points for each Toroidal Field (TF) coil and in particular the proposed procedure for the final assembly of the TF magnet system.
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The JT-60SA Toroidal Field Magnet—Design for Assembly
IEEE Transactions on Applied Superconductivity, 2012Co-Authors: S Davis, D Duglue, N Hajnal, G Phillips, P. Barabaschi, Kazuki Shibanuma, Valerio TomarchioAbstract:The JT-60SA experiment will be the world's largest superconducting tokamak when it is assembled in Naka, Japan (R = 3 m, a = 1.2 m). This paper describes the approach taken to define appropriate manufacturing tolerances and metrology points for each Toroidal Field (TF) coil and in particular the proposed procedure for the final assembly of the TF magnet system.
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design of the jt 60sa superconducting Toroidal Field magnet
IEEE Transactions on Applied Superconductivity, 2010Co-Authors: Valerio Tomarchio, D Duglue, P. Barabaschi, A. Cucchiaro, P. Decool, A. Della Corte, A. Di Zenobio, L Meunier, L Muzzi, M NanniniAbstract:The JT-60SA is a fusion experiment designed to contribute to the early realization of fusion energy, by providing support to the operation of ITER, by addressing key physics issues for ITER and DEMO and by investigating how best to optimize the operation of the next fusion power plants that will be built after ITER. It is a combined project of the JA-EU Satellite Tokamak Program under the Broader Approach (BA) Program and JAEA's Program for National Use, and it is to be built in Naka, Japan, using the infrastructure of the existing JT-60U experiment. This paper describes in detail the design of the JT-60SA Toroidal Field magnet and shows the strong points of each foreseen solution. Additional information about manufacturing procedures is given and technological issues are reported and critically analysed.
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Effects of enhanced Toroidal Field ripple on JET plasmas
Plasma Physics and Controlled Fusion, 1992Co-Authors: G.j. Sadler, P. Barabaschi, E. Bertolini, Sean Conroy, S. Corti, E.b. Deksnis, K.j. Dietz, H.p.l. De Esch, A. Gondhalekar, B.j. GreenAbstract:The JET machine is equipped with 32 Toroidal Field coils. In order to study the effect of TF ripple on the confinement of fast particles and, more generally, on the plasma behaviour, a series of experiments was performed using only 16 TF coils. At the position of the outer limiter, this led to an increase of the ripple, delta =(Bmax-Bmin)/(Bmax+Bmin), from 1% to 12.5%. The Toroidal Field was limited to 1.4 T, with plasma currents in the range between 2 and 3 MA. Additional heating power-levels and energy-input were kept low in order to avoid possible damage to some first wall components made out of Inconel. Experiments were carried out using 140 keV NBI injected deuterons, ICRF accelerated protons and deuterons ( approximately 0.5 to approximately 2 MeV) and 1 MeV tritons from DD reactions.
Yasuhiro Suzuki - One of the best experts on this subject based on the ideXlab platform.
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Design of simple stellarator using tilted Toroidal Field coils.
arXiv: Plasma Physics, 2020Co-Authors: Yasuhiro Suzuki, Jie Huang, Nengchao Wang, Yonghua DingAbstract:This paper deals with the design of the stellarator Field with the simple coil set. In order to realize the stellarator Field by the simple coil set, the tilted Toroidal Field coil uses for creating the rotational transform. Sixteen tilted TF coils create the small radial Field and large vertical Field. With reducing the vertical Field of the tilted Toroidal Field coil by the axisymmetric poloidal Field coil, the stellarator Field can be made. The formation of clear and nested flux surfaces is confirmed, and the rotational transform is proportional to the tilting angle of the Toroidal Field coil. Main components of the magnetic Field for the simple stellarator in this paper are the large mirror ripple and small helical ripple. This is a similar property to the quasi-isodynamic configuration like the Wendelstein 7-X stellarator. The collisionless orbit for the proton is studied. For a moderate tilting angle of the Toroidal Field coil, the confinement of the passing and trapped particles improves.
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Finite beta effects on the Toroidal Field ripple in three-dimensional tokamak equilibria
Nuclear Fusion, 2003Co-Authors: Yasuhiro Suzuki, Yuji Nakamura, Katsumi KondoAbstract:In order to investigate finite beta effects on the Toroidal Field ripple in a tokamak, three-dimensional free-boundary magnetohydrodynamics (MHD) equilibria are studied for a tokamak configuration that has an aspect ratio of 3.5 and an almost circular cross-section. Equilibria that are consistent with the non-axisymmetric external magnetic Field are obtained by the VMEC code with a prescribed safety factor profile. To study tokamak configurations with a free-boundary constraint, we modify the boundary condition to specify the plasma position and size in the VMEC code. From the equilibria obtained, the change of the Toroidal Field ripple due to the finite pressure is calculated and the three-dimensional MHD effect on the ripple is estimated. In a finite pressure equilibrium, the Toroidal ripple is changed by the equilibrium plasma current. The influence of the purely three-dimensional MHD effect on the Toroidal Field ripple is not large but the ripple is also changed by the variation of the axisymmetric component in finite pressure equilibria. In a medium-beta equilibrium, high energy particle confinement changes significantly due to the variation of the ripple well depth along the Field line, because of the Shafranov shift, the change of the magnetic Field line pitch due to the Pfirsch–Schluter current, and the above mentioned finite pressure effect on the Field ripple.
Peter A Gilman - One of the best experts on this subject based on the ideXlab platform.
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baroclinic instability in the solar tachocline for continuous vertical profiles of rotation effective gravity and Toroidal Field
The Astrophysical Journal, 2017Co-Authors: Peter A GilmanAbstract:We present results from an MHD model for baroclinic instability in the solar tachocline that includes rotation, effective gravity, and Toroidal Field that vary continuously with height. We solve the perturbation equations using a shooting method. Without Toroidal Fields but with an effective gravity declining linearly from a maximum at the bottom to much smaller values at the top, we find instability at all latitudes except at the poles, at the equator, and where the vertical rotation gradient vanishes (323) for longitude wavenumbers m from 1 to >10. High latitudes are much more unstable than low latitudes, but both have e-folding times that are much shorter than a sunspot cycle. The higher the m and the steeper the decline in effective gravity, the closer the unstable mode peak to the top boundary, where the energy available to drive instability is greatest. The effect of the Toroidal Field is always stabilizing, shrinking the latitude ranges of instability as the Toroidal Field is increased. The larger the Toroidal Field, the smaller the longitudinal wavenumber of the most unstable disturbance. All latitudes become stable for a Toroidal Field exceeding about 4 kG. The results imply that baroclinic instability should occur in the tachocline at latitudes where the Toroidal Field is weak or is changing sign, but not where the Field is strong.
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Analysis of Instability of Latitudinal Differential Rotation and Toroidal Field in the Solar Tachocline Using a Magnetohydrodynamic Shallow-Water Model. I. Instability for Broad Toroidal Field Profiles
The Astrophysical Journal, 2002Co-Authors: Peter A Gilman, Mausumi DikpatiAbstract:We examine the global MHD instability of solar tachocline latitudinal differential rotation and the coexisting broad Toroidal magnetic Field, using a "shallow-water" model that captures the simplest effects of subadiabatic stratification. We assume a single fluid shell that has a fixed bottom but variable thickness. This model is the MHD generalization of a hydrodynamic model that we have previously applied to the tachocline, although the solution method is somewhat different. Stratification in the model is characterized by an "effective gravity" G (G = 0 for adiabatic stratification). The radiative (lower) part of the tachocline thus has high G (~102) and the overshoot part, low G (less than 1). We obtain growth rates, phase velocities, and spatial structures of unstable modes for a wide range of Toroidal Field strengths and effective gravities, as well as differential rotations that are consistent with helioseismic observations. We recover known two-dimensional MHD stability results in the limit of large G and hydrodynamic instability results in the limit of vanishing Toroidal Field. For strong magnetic Fields, only longitudinal wavenumber m = 1 is unstable, but for weak Fields m = 2 is also. For peak Toroidal Fields of 20 kG and above, the growth rates and disturbance structures are essentially independent of the effective gravity, until it becomes so small that the fluid shell shrinks to zero in low latitudes, whereupon the instability is cut off. In contrast, the instability evolves radically at low G when Toroidal Field is increased from zero. In both overshoot and radiative parts of the tachocline, unstable modes grow fastest for Toroidal Fields of the order of 102 kG. The structure of the unstable disturbances is always governed by the latitude location of singular or critical points at which the Doppler-shifted phase velocity of the disturbance equals the local (angular) Alfven speed. All unstable disturbances possess kinetic helicity, narrowly concentrated in the neighborhood of the same critical points. Just as shown by Dikpati & Gilman for the hydrodynamic case, such disturbances could provide an "α-effect" for the solar dynamo. But unlike the hydrodynamic case, this α-effect would be a function of the Toroidal Field itself.
P. Decool - One of the best experts on this subject based on the ideXlab platform.
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design of the jt 60sa superconducting Toroidal Field magnet
IEEE Transactions on Applied Superconductivity, 2010Co-Authors: Valerio Tomarchio, D Duglue, P. Barabaschi, A. Cucchiaro, P. Decool, A. Della Corte, A. Di Zenobio, L Meunier, L Muzzi, M NanniniAbstract:The JT-60SA is a fusion experiment designed to contribute to the early realization of fusion energy, by providing support to the operation of ITER, by addressing key physics issues for ITER and DEMO and by investigating how best to optimize the operation of the next fusion power plants that will be built after ITER. It is a combined project of the JA-EU Satellite Tokamak Program under the Broader Approach (BA) Program and JAEA's Program for National Use, and it is to be built in Naka, Japan, using the infrastructure of the existing JT-60U experiment. This paper describes in detail the design of the JT-60SA Toroidal Field magnet and shows the strong points of each foreseen solution. Additional information about manufacturing procedures is given and technological issues are reported and critically analysed.
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JT-60SA Toroidal Field Magnet System
IEEE Transactions on Applied Superconductivity, 2008Co-Authors: A. Pizzuto, L. Zani, N. Dolgetta, P. Decool, L. Semeraro, P. Bayetti, Antonio Cucchiaro, A. Della Corte, A. Di Zenobio, Jl. DuchateauAbstract:The broader approach agreement between Europe and Japan includes the construction of a fully superconducting tokamak, the JT-60 Super Advanced (JT-60SA), as a satellite experiment to ITER. In particular, the whole Toroidal Field magnet system, described in this paper, will be provided to Japan by the EU. All the TF coil main constituents, i.e. conductor, winding pack, joints, casing, current leads, are here presented and discussed as well as the design criteria adopted to fulfil the machine requirements. The results of the analyses performed by the EU and JA to define and assess the TF magnet system conceptual design are reported and commented. Future work plan is also discussed.
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Mechanical tests of the ITER Toroidal Field model coil
IEEE Transactions on Appiled Superconductivity, 2004Co-Authors: P. Libeyre, N. Dolgetta, P. Decool, S. Raff, P. Schanz, F. Wuechner, H. FillungerAbstract:The International Thermonuclear Experimental Reactor (ITER) Toroidal Field model coil (TFMC) was designed to allow an overall mechanical test representative of the ITER Toroidal Field (TF) coils design principles and features. The coil, manufactured by the European industry, was tested in two phases at the TOSKA facility of the Forschungszentrum Karlsruhe up to its maximum current of 80 kA. In the single coil tests performed in 2001 the coil was submitted to in-plane loading only, whereas in the two coil tests performed in 2002 the coil experienced also out-of-plane loading, representative of the coil load conditions in the ITER tokamak TF magnet. The paper details the mechanical tests performed, compares them to model predictions and discusses the experience gained in the mechanical behavior of the ITER TF coils.
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completion of the iter Toroidal Field model coil
Symposium On Fusion Technology, 2001Co-Authors: R. Maix, P. Libeyre, P. Decool, H. Fillunger, E. Salpietro, Neil Mitchell, F Hurd, A Ulbricht, G Zahn, A. Della CorteAbstract:In the scope of the ITER EDA a Toroidal Field Model Coil (TFMC) has been manufactured accompanied by a thorough Quality Assurance (QA) test program. This large superconducting coil has been conceptually designed by the ITER European Home Team (EUHT) and manufactured by European industry. The coil is being completed and will be tested at the Forschungszentrum Karlsruhe in spring 2001. The race track shaped winding is made of a cable-in-conduit conductor in a circular 316LN stainless steel jacket. From this conductor five double pancake (DP) modules were fabricated. Results of conductor and DP manufacture were already presented at previous conferences and are therefore only summarized here. The paper concentrates on the subsequent manufacturing steps, namely the stacking of the DP modules, the insulation and impregnation of the winding pack, the outer joint manufacture by electron beam welding, the assembly of the winding pack with the stainless steel case, the mounting of the helium pipes, the sensors and the busbars. To assemble the coil into the TOSKA facility and to fit it to the EU-LCT coil a heavy Inter-Coil Structure (ICS) has been built, in which the TFMC will rest on four wedges.
Tamara M. Rogers - One of the best experts on this subject based on the ideXlab platform.
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Toroidal Field Reversals and the Axisymmetric Tayler Instability
The Astrophysical Journal, 2011Co-Authors: Tamara M. RogersAbstract:We present axisymmetric numerical simulations of the solar interior, including the convection zone and an extended radiative interior. We find that differential rotation in the convection zone induces a Toroidal Field from an initially purely poloidal Field. This Toroidal Field becomes unstable to the axisymmetric Tayler instability and undergoes equatorward propagating Toroidal Field reversals. These reversals occur in the absence of a dynamo and without accompanying poloidal Field reversals. The nature and presence of such reversals depends sensitively on the initial poloidal Field strength imposed, with north-south symmetric reversals only seen at a particular initial Field strength. Coupled with a dynamo mechanism which regenerates the poloidal Field this could be one ingredient in the sunspot cycle.
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Toroidal Field Reversals
Proceedings of the International Astronomical Union, 2010Co-Authors: Tamara M. RogersAbstract:AbstractI present axisymmetric numerical simulations of the solar interior, with differential rotation imposed in the convection zone and tachocline and a dipolar poloidal Field confined to the radiative interior. In these simulations Toroidal Field reversals which are equator-ward propagating are driven in the absence of a dynamo. These reversals are driven in the tachocline and are seen at the top of the convection zone. While not solar-like in many ways, these reversals do show some solar-like properties not previously seen in full MHD simulations.
