Non-adiabatic compression of elongated field-reversed configurations

Magnetic compression is a simple and efficient method of heating plasma. In a field-reversed configuration magnetic confinement device, the plasma inevitably encounters various losses during the magnetic compression process, including flux loss, energy loss, and particle loss. These losses have significant effects on the magnetic compression process in field-reversed configuration. In this study, a non-adiabatic magnetic compression model is constructed, taking into account the confinement times of flux, energy, and particles, on the basis of the research results of Spencer et al. [Phys. Fluids. 26, 1564–1568 (1983)]. In the model, the scaling law between four key parameters, namely, radius ratio, length, density, and temperature, and the compressive magnetic field is derived. The non-adiabatic magnetic compression model incorporating multiple losses is compared to the adiabatic magnetic compression model, with analysis of the effects of three loss types, magnetic field rise time, and magnetic field compression ratio on four key plasma parameters. Furthermore, the model's analytical solution is compared with the magnetic compression experiment data from Rej et al. [Phys. Fluids B 4, 1909 (1992)]. It is of great significance for the design of the magnetic compression scheme and the understanding of the experimental results.