Design and test of a control system for the EAST laser blow-off impurity injection system

Abstract

BackgroundStudying the transport behavior of impurities in plasma and developing effective impurity control methods are important for achieving high-performance plasma discharge and ensuring the safe operation of the device.PurposeThis study aims to design a control system for the experimental advanced superconducting Tokamak (EAST) laser blow-off (LBO) impurity system.MethodsA new automatic control process was adopted to enable to inject tracer particles of different elements into the EAST plasma repeatedly, quantitatively, and controllably. An accurate control of the focusing lens displacement and laser triggering time were achieved through the STM32 microcontroller system and its output PWM waves for stepper motor driving, hence the diameter of the laser spot was adjustable to change the amount of impurities injected. Finally, the designed control system for LBO was tested in staging environment to verify its practicability and accuracy.ResultsThe test results show that the system can rapidly detect the external trigger signal and achieve precise timing, with less than 0.4 mm position error for laser spot focusing.ConclusionsThe design of control system meets the requirements of the laser blowing impurity injection experiment. This study is of considerable significance for research on EAST plasma impurity transport.

Keywords

• laser blow-off impurity injection system
• impurity transport
• stm32
• control system