A swept Langmuir probe diagnostic for non-Maxwellian divertor plasmas on EAST

A swept Langmuir probe diagnostic framework has been developed for the Experimental Advanced Superconducting Tokamak. The hardware features 8-channel swept Langmuir probe array equipped with a dynamic-gain sampling circuit, enhancing anti-saturation performance and achieving an order-of-magnitude noise reduction (root-mean-square error ~ 0.004 A) for low-current resolution. For data processing, a bi-Maxwellian current decomposition method is employed to decouple non-ideal high-energy signal components arising from non-Maxwellian electron energy distribution functions. This approach mitigates the systematic overestimation of bulk electron temperature inherent to conventional single-Maxwellian methods. Validated by synthetic data tests, the framework demonstrated high operational reliability during a 404 s steady-state H-mode discharge and successfully tracked cooling dynamics in impurity-induced detachment scenarios. Overcoming conventional signal processing bottlenecks, this system provides a highly reliable parameter extraction solution for boundary physics studies in tokamaks.