LAUSR

Ionospheric heating by high‐power electromagnetic waves is a powerful and efficient tool to study plasma physics as the ionosphere is used as a nature plasma laboratory. An important and long‐standing issue is how to improve the heating efficiency. It is difficult to uncover all the underlying physical processes that influence the heating efficiency in actual ionospheric experiments. Therefore, controlled experiments have been designed and conducted in a laboratory plasma facility to study the high‐frequency heating processes in an ionospheric‐like collisional plasma. The energy of the injected wave was transferred into the plasma through nonlinear interactions, such as the parametric decay instability (PDI). Our results suggest that the existing background wave mode could significantly decrease the excitation threshold of the parametric instability, indicating that the PDI can be much easily excited.