Analysis of eddy currents in the two-half isolated vacuum vessel of an iron core tokamak

2015 ◽  
Vol 101 ◽  
pp. 80-87 ◽  
Author(s):  
L.J. Liu ◽  
B. Rao ◽  
M. Zhang ◽  
K.X. Yu ◽  
G. Zhuang
2020 ◽  
Vol 86 (5) ◽  
Author(s):  
R. Sweeney ◽  
A. J. Creely ◽  
J. Doody ◽  
T. Fülöp ◽  
D. T. Garnier ◽  
...  

SPARC is being designed to operate with a normalized beta of $\beta _N=1.0$ , a normalized density of $n_G=0.37$ and a safety factor of $q_{95}\approx 3.4$ , providing a comfortable margin to their respective disruption limits. Further, a low beta poloidal $\beta _p=0.19$ at the safety factor $q=2$ surface reduces the drive for neoclassical tearing modes, which together with a frozen-in classically stable current profile might allow access to a robustly tearing-free operating space. Although the inherent stability is expected to reduce the frequency of disruptions, the disruption loading is comparable to and in some cases higher than that of ITER. The machine is being designed to withstand the predicted unmitigated axisymmetric halo current forces up to 50 MN and similarly large loads from eddy currents forced to flow poloidally in the vacuum vessel. Runaway electron (RE) simulations using GO+CODE show high flattop-to-RE current conversions in the absence of seed losses, although NIMROD modelling predicts losses of ${\sim }80$  %; self-consistent modelling is ongoing. A passive RE mitigation coil designed to drive stochastic RE losses is being considered and COMSOL modelling predicts peak normalized fields at the plasma of order $10^{-2}$ that rises linearly with a change in the plasma current. Massive material injection is planned to reduce the disruption loading. A data-driven approach to predict an oncoming disruption and trigger mitigation is discussed.


1996 ◽  
Vol 32 (4) ◽  
pp. 3004-3007 ◽  
Author(s):  
H. Bohn ◽  
B. Giesen ◽  
A. Belov ◽  
N. Berkhov ◽  
E. Bondarchuk ◽  
...  

2005 ◽  
Vol 45 (7) ◽  
pp. 675-684 ◽  
Author(s):  
G.O Ludwig ◽  
E. Del Bosco ◽  
J.G Ferreira

1995 ◽  
pp. 211-214
Author(s):  
P. Collarin ◽  
P. Sonato ◽  
P. Zaccaria ◽  
G. Zollino
Keyword(s):  

Author(s):  
Andrzej Waindok ◽  
Pawel Piekielny

Purpose The purpose of this paper is to calculate and measure transients for two different constructions of electrodynamic accelerators (ironless and iron-core) supplied by a three-section power system (three capacitor banks). The optimization of power supply parameters (switch-on times and capacitances of individual sections) in terms of system efficiency has been carried out. Design/methodology/approach Calculations have been carried out using a field-circuit model. For three-dimensional magnetostatic analysis, the Maxwell software and finite element method (FEM) were used, while for circuit model, the Matlab/Simulink software was implemented. For optimization of the supply system parameters, the genetic algorithm was used. The mathematical models were verified experimentally by using the original laboratory stand. Findings The efficiency of the system is much higher in case of iron-core accelerator. In both cases, the results obtained for optimized supply settings are only slightly better than those obtained by simultaneously switching on the thyristors and for symmetrical capacity division. Research limitations/implications Due to the presented field-circuit model, eddy currents in rails have been neglected. In the field model, there was no possibility to combine current flow calculations with moving of the projectile. Originality/value Using the presented filed-circuit model, both electrical and mechanical transients could be calculated with sufficient precision. Thus, it could be used in the optimization of supply system. The solution time is low compared with the solution time of the transient field model.


2001 ◽  
Vol 58-59 ◽  
pp. 845-849 ◽  
Author(s):  
F.H. Bohn ◽  
G. Czymek ◽  
B. Giesen ◽  
E. Bondarchuk ◽  
N. Doinikov ◽  
...  

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