A novel magnetic island structure identification system based on Mirnov probes and DDR3 look-up table for HL-2A tokamak

Abstract

A: A novel magnetic island structure identification (MISI) system based on Mirnov probes and DDR3 look-up table has been developed on the HL-2A device. The system is dedicated to identify the magnetic island by analyzing the measurement of Mirnov probes and equilibrium fitting (EFIT) code. The applications of high-precision sampling and PCI express (PCIe) platform in the system provides the convenience for Mirnov measurements and the EFIT results transmission. A high performance field programmable gate array (FPGA) is used to realize the real-time identification algorithm. By applying the DDR3 look-up table, 30 current filaments are arranged on a 129 × 129 grid in the calculation of perturbation flux, simplifying the algorithm structure and improving the efficiency. For the advantage of parallel and pipeline processing abilities in the FPGA, the magnetic island structure can be identified with time resolution of 3 ms and spatial resolution of 1.37 cm and 1.02 cm.

An FFT overlap method for high bandwidth far-infrared laser Interferometer in HL-2A

“…Compared with the conventional analog phase detection techniques, digital phasemeter provides better flexibility for implementing different strategies in different situations [18][19][20]. Moreover, it can achieve a high Signal-Noise Rate (SNR) in data transforming and processing.…”

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

“…At present, the common methods to identify the magnetic island structure include soft x-ray tomography and electron cyclotron radiation [3][4][5][6]. In the HL-2A tokamak device, the MHD instabilities, especially the tearing modes, are investigated by Mirnov probes, and the magnetic island reconstruction (MIR) method on the basis of Mirnov signals and the equilibrium fit (EFIT) code has been developed gradually in recent years [7][8][9]. In this method, the mode number of the tearing mode can be firstly obtained by analyzing the Mirnov signals, and the real perturbation field is simulated by the magnetic field induced by the perturbation current distributed on the rational surface.…”