Development of a real-time magnetic island reconstruction system based on PCIe platform for HL-2A tokamak

A real-time magnetic island reconstruction (MIR) system based on PCI express platform for HL-2A tokamak is introduced. The front-end analog circuit and high performance analog-to-digital converters complete high-precision synchronous sampling of 18 channel Mirnov signals, and the application of PCIe platform and direct memory access technology enables high speed data transmission between graphics processing unit and field programmable gate array (FPGA). FPGA, as a mainstream high speed parallelizable computing tool, was used to implement the MIR algorithm, while a parameter table is established in an external double data rate SDRAM to improve the computational efficiency. The software of the MIR system is developed with Compute Unified Device Architecture 8.0 in Centos 6 system, which mainly realizes driver development, data transmission, network communication, parameter calculation and system control. This system has been tested in HL-2A plasma discharge experiment, and the reconstructed magnetic island structure can achieve a spatial resolution of 1.02 cm while the time resolution can reach 2 ms.