This paper shows the magneto-thermal dynamics of a quench in a HTS solenoid protected by a dump resistor. The analysis is carried out using a field/circuit coupling technique with the waveform relaxation scheme, implemented in the STEAM co-simulation framework. The field model implements a coupled field formulation for superconducting materials combined with solid conductors, and accounts for the dynamics of the solenoid. The circuit model is implemented in a network solver, which accounts for the the supply and protection circuitry. The approach is verified with a monolithic model. It allows for analyzing arbitrarily complex models, such as the circuits of superconducting magnets in particle accelerators.