Study on nonlinear effects of intense electromagnetic irradiation on aluminum-coated thermal control films in vacuum

Spacecraft thermal control film materials are subjected to a variety of complex environmental fields in complex environments. To study their damage behavior patterns under intense electromagnetic irradiation, using aluminum-coated thermal control films as a typical example, relying on the atmospheric plasma experimental platform, when comparing different air pressures and different microwave output parameters, the differences in damage behavior of thermal control film materials under S-band (2.92 GHz) microwave irradiation are studied. Through analyses such as real-time video, post-test damage morphology, and performance characterization of the materials, it was found that, unlike the absence of discharge flash at normal pressure, the surface damage of the thermal control film was obvious in a low-pressure environment, showing the characteristics of a nonlinear damage effect dominated by pressure. The damage creepage of the aluminum-coated film followed reticular or tree-branch fractal patterns, accompanied by surface melting marks. Based on the typical experimental phenomena, a simplified physical model including field emission, secondary electron multiplication, surface outgassing, and gas collision ionization was established, and the effects of these processes on the aluminum-coated film were analyzed. This study supplements the experimental data and theoretical support for research on the mechanism of multi-physics field synergy and provides an important reference for the practical application of thermal control systems in future spacecraft.