[1] High Power Auroral Stimulation (HIPAS) Observatory and High Frequency Active Auroral Research Program (HAARP) are two radiating facilities in the Arctic region separated by a distance of the order of VLF wavelengths. The current-carrying plasma in the E region of the ionosphere above each facility can be modulated to radiate VLF waves via HF heating. Experiments demonstrated that VLF waves can be coherently excited by these two facilities through constructive interference that is sensitive to the phase difference between these two sources.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.