Detached plasma dynamics under transient upstream perturbations were investigated in the divertor simulation module of GAMMA 10/PDX using double-pulse central electron cyclotron heating (C-ECH) to generate controlled transient heat and particle fluxes. Detached plasma was produced by radiator gas injection, and its temporal evolution was measured with electrostatic probes, Thomson scattering, microwave interferometry, and high-speed Balmer-line imaging. The intermittent particle fluxes generated by C-ECH induced rapid and repeatable transitions between detached and attached states, with characteristic collapse and recovery times of approximately 1 ms. Spatiotemporal Hα/Hβ measurements revealed a transient, heating-driven shift of the recombining (MAR-dominated) region toward the target plate, accompanied by a transition to an ionization-dominated regime. Comparison with a collisional-radiative model indicates that the observed variations in Hα/Hβ reflect temperature-driven changes in excitation and recombination processes, although the line-integrated nature of the measurement limits quantitative comparison. The response times are comparable to those reported in Magnum-PSI transient-pulse experiments, demonstrating that detachment stability is sensitive to millisecond-scale perturbations across different magnetic configurations and plasma species. These results establish double-pulse C-ECH as a precise actuator for studying and controlling detachment-like plasma states in the end region of mirror devices.
Dynamic response of atomic processes in detached helium plasma induced by high-density transient pulse in Magnum-PSI