The Challenge for Adiabatically Heated FRC Based D-He Fusion

The performance requirements of fusion reactors based on FRC adiabatic compression with a D-He fuel are discussed. Assuming thermonuclear reaction rates, confinement times exceeding 10 ms are required for peak magnetic fields below 25 T. The typical thermodynamic cycle of such reactors in current/flux variables is computed. The fact that most magnetic energy is channeled to vacuum magnetic energy, instead of heating the plasma, translates into a very elongated thermodynamical cycle. The consequences for the viability of this type of reactors are discussed.