Design of a Pop-Up Divertor Langmuir Probe System for the HL-3 Tokamak

A novel pop-up divertor Langmuir probe system is developed for measuring the plasma parameters on divertor target plates in HL-3 tokamak. The system enables reliable ejection and retraction in strong magnetic-field environments and adopts a modular design consisting of a probe assembly, a drive support unit, and a coil box assembly. This configuration allows flexible adjustment to enhance spatial resolution and minimize installation space. Dynamic and thermodynamic analyses demonstrate that the system can operate stably under strong magnetic fields and high heat loads, and extend probe service life. The system has been successfully installed on the HL-3 tokamak with preliminary experimental validation, verifying its feasibility for accurate in-situ measurements of divertor plasma parameters.