The 8th International Conference on Matter and Radiation at Extremes (ICMRE2025)

Magneto-inertial fusion (MIF) based on the field-reversed configuration (FRC)—a self-organized, high‑β plasma—offers moderate plasma density and confinement time compared to both magnetic and inertial confinement fusion, which considerably reducing the cost of fusion devices. To guide the design and construction of HHMAX‑901 device, we investigate stable control schemes for FRC plasma in a linear device using magnetohydrodynamic (MHD) simulations, which include the dynamic formation of FRC, axial transport, and collision fusion processes.
Our device is designed with three distinct zones: formation, acceleration‑compression, and collision. In the formation zones, located at both ends of the device, FRC plasma is generated inside a quartz tube using dynamic θ‑pinch technology. In the subsequent acceleration‑compression zones, well‑controlled magnetic pulses combined with the conical geometry of the tube serve to increase the plasma density, temperature, and axial translation speed. In the central collision zone, the kinetic energy of FRCs translating along the axial direction (with a relative speed of 400–600 km/s) is converted into thermal energy during collisions. It is expected that the resulting quasi‑adiabatic compression, induced by a high magnetic field, will significantly improve plasma parameters and lead to implosion.
Our simulation results indicate that plasma mass loss primarily arises from particles escaping along the axial direction, and that distortion of the magnetic surface adversely affects the axial acceleration of FRC plasma. Analysis under varying parameters reveals that optimizing the magnetic field gradient in conjunction with the tube geometry significantly suppresses wall deposition, while enhancing the axial magnetic field effectively prolongs flux‑trapping time and controls the FRC plasma speed. These findings are valuable for the design of the HHMAX‑901 device, particularly in terms of predicting magnetic field gradients and timing control.
The developed MHD simulation is capable of quantitatively predicting the dynamic transport of FRC plasma, providing a theoretical foundation for novel MIF technology. The results have been successfully applied in the design and construction of the HHMAX‑901 device.
 

Plasma transport,Field-reversed configuration (FRC),Magnetohydrodynamic