Abstract:
Background The integration of free-electron laser, strong magnetic field, and ultralow-temperature environments is a core direction of multi-disciplinary frontier research. As the key component of the free-electron laser-microwave power source system, solid-state high-voltage modulators directly determine the performance and operational stability of the Free Electron Laser & High Magnetic Field Device.
Purpose This study aims to develop a high-voltage solid-state modulator that meets the parameter requirements of the Device, establish a refined circuit-magnetic circuit model for its topology, and verify the model’s accuracy to support subsequent research on the modulator system and klystrons.
Methods Guided by the Device’s specifications, the modulator topology was determined based on the inductive superposition principle. The discharge unit scheme was designed, and a fractional-ratio pulse transformer was selected to achieve a 1:345 voltage boost ratio. A refined model was constructed, including modular discharge unit modeling, fractional-ratio pulse transformer modeling based on magnetic reluctance theory, and klystron modeling. Dummy load experiments and klystron load tests were conducted to validate the model.
Results The fabricated modulator achieves the designed parameters of 310 kV, 320 A, 10 μs pulse width, and 10 Hz repetition frequency. Experimental and simulated waveforms show excellent agreement in the pulse leading edge and flat-top regions, with nearly complete overlap, which initially verifies the model’s accuracy.
Conclusions The developed modulator meets the operational requirements of the Free Electron Laser & High Magnetic Field Device, and the established refined model exhibits high reliability. This work lays a solid foundation for in-depth research on the modulator system and klystrons, and provides essential experimental support for multi-disciplinary frontier studies relying on the Device.