Abstract
DEMETER spacecraft observations of ELF signals generated by the recently upgraded High‐Frequency Active Auroral Research Program (HAARP) HF facility (3.6 MW) reveal three distinctive regions characterizing upgoing ELF waves. These regions are classified by signal intensity and the minimum lateral distance d between the magnetic footprint of the satellite at 75‐km altitude (D layer) and the point at 75‐km altitude immediately above HAARP where the source is located. The first large region within d ≃ 900 km contains waves which propagate in the Earth‐ionosphere waveguide and then leak upward to the spacecraft. The second region of d ≃ 200–300 km contains waves propagating to the spacecraft from the ionospheric source region without reflection from the ground. The third region contains waves of very high intensity (E ≃ 350 μV/m, B ≃ 20 pT) within a narrow cylindrical column of ∼10–20 km radius, also observed once before on the ISIS 1 spacecraft. The observed intense columnar radiation is consistent with predictions of a recent full‐wave model of ELF radiation from HF‐heater‐produced ionospheric source currents.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
