Influence of plasma diagnostics and constraints on the quality of equilibrium reconstructions on Joint European Torus

摘要: One of the main approaches to thermonuclear fusion relies on confining high temperature plasmas with properly shaped magnetic fields. The determination topology is, therefore, essential for controlling experiments and achieving required performance. In Tokamaks, reconstruction fields is typically formulated as a free boundary equilibrium problem, described by Grad-Shafranov equation in toroidal geometry axisymmetric configurations. Unfortunately, this results mathematically very ill posed problems and, quality reconstructions depends sensitively measurements used inputs imposed constraints. paper, it shown how different diagnostics (Magnetics Measurements, Polarimetry Motional Stark Effect), together edge current density plasma pressure constraints, can have significant impact JET. Results show that both Effect internal are crucial order obtain reasonable safety factor profiles. constraint when H-mode confinement. scenario strike point positions last closed flux surface change even centimetres, depending remapping equilibrium-dependent pedestal physics studies. On other hand quite counter intuitively, severely affect core. These trends been verified several JET discharges consistent found. An interpretation these results, interplay between degrees freedom available measurements, provided. systematic analysis paper emphasizes importance having sufficient diagnostic validating codes independent measurements.