Attapon P.Suksaengpanomrung S.Dang-iad A.Tamman A.Buaruk S.Chatthong B.Promping J.Wonghabut P.Nilgumhang K.Kongprawes G.Poolyarat N.Onjun T.Wisitsorasak A.Mahidol University2026-03-312026-03-312026-06-01Fusion Engineering and Design Vol.227 (2026)09203796https://repository.li.mahidol.ac.th/handle/123456789/115916Precise determination of the plasma column position is fundamental for equilibrium maintenance and stability control in tokamak devices. This work presents a comparative study of two methodologies implemented on the Thailand Tokamak-1 (TT-1): a Toroidal Filament Model using circumferentially oriented Mirnov probes and an Optical Boundary Reconstruction (OBR) technique based on high-speed visible imaging. The filament model provides a rapid analytical solution ((Formula presented) per time slice) for the plasma centroid and is adaptable, allowing many different combinations of magnetic probes to be used in the event of malfunctioning probes, while the optical method serves as a direct geometric cross-validation tool. Experimental results from Ohmic discharges demonstrate strong agreement between the two methods during stable flat-top phases, with radial and vertical displacement trends consistent within experimental margins. However, discrepancies observed during dynamic phases are analyzed in the context of magnetic noise contributions and optical emission limitations. During this dynamic phase, the OBR technique fails to calculate the plasma column position due to optical limitations, whereas the filament model remain functional throughout the discharge. Because of its speed and consistency, the study confirms the viability of the Toroidal Filament Model for future real-time feedback control systems in TT-1.Materials ScienceEnergyEngineeringArticleSCOPUS10.1016/j.fusengdes.2026.1156962-s2.0-105033086336