A crucial issue in magnetically confined plasmas characterized by relevant internal current redistribution, such as high beta and low field toroidal devices, is the determination of their internal magnetic structure. The article presents a method for the integration of magnetic and nonmagnetic measurements in a model which considers a plasma described by stationary ideal magnetohydrodynamic equilibrium equations, with toroidal and poloidal plasma currents represented by distributed discrete filaments and current sheets. The model also includes the massive conductors representing the vessel, the shell, and the machine windings. The discrete current sets are determined by using as input data the total currents flowing in the plasma, in the windings and in the vessel, as deduced by external integral magnetic measurements. The obtained filamentary current sets are then adjusted by imposing further constraints. One of the constraints is given by the set of local magnetic field measurements provided by external pickup coils. A further and more significant constraint is imposed by far infrared polarimeter, which gives an integral condition for each implemented measurement chord. The method is validated by using experimental data from the reversed field pinch Reversed Field eXperiment, and the results suggest that the current density distribution is rather different from that usually predicted by conventional data inversion algorithms.

Integration of magnetic and nonmagnetic measurements for current profile reconstruction in RFX

BAGATIN, MARIO;CHITARIN, GIUSEPPE;DESIDERI, DANIELE;
2001

Abstract

A crucial issue in magnetically confined plasmas characterized by relevant internal current redistribution, such as high beta and low field toroidal devices, is the determination of their internal magnetic structure. The article presents a method for the integration of magnetic and nonmagnetic measurements in a model which considers a plasma described by stationary ideal magnetohydrodynamic equilibrium equations, with toroidal and poloidal plasma currents represented by distributed discrete filaments and current sheets. The model also includes the massive conductors representing the vessel, the shell, and the machine windings. The discrete current sets are determined by using as input data the total currents flowing in the plasma, in the windings and in the vessel, as deduced by external integral magnetic measurements. The obtained filamentary current sets are then adjusted by imposing further constraints. One of the constraints is given by the set of local magnetic field measurements provided by external pickup coils. A further and more significant constraint is imposed by far infrared polarimeter, which gives an integral condition for each implemented measurement chord. The method is validated by using experimental data from the reversed field pinch Reversed Field eXperiment, and the results suggest that the current density distribution is rather different from that usually predicted by conventional data inversion algorithms.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2461974
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