Fejer, J.A.Ierkic, H.M.Woodman Pollitt, Ronald FranciscoRöttger, J.Sulzer, M.Behnke, R.A.Veldhuis, A.2016-11-082017-12-212016-11-082017-12-211982Fejer, J. A., Ierkic, H. M., Woodman, R. F., Röttger, J., Sulzer, M., Behnke, R. A., & Veldhuis, A. (1982). Observations of the HF-enhanced plasma line with a 46.8MHz radar and reinterpretation of previous observations with the 430 MHZ radar.==$Journal of Geophysical Research: Space Physics, 88$==(A3), 2083-2092. https://doi.org/10.1029/JA088iA03p02083http://hdl.handle.net/20.500.12816/600During 5.1 MHz HF transmissions below the F-region penetration frequency by a nearby ionospheric modification facility, radar echoes coming from F-region heights at a frequency of 46.8 + 5.1 = 51.9 MHz were received while a VHF radar using the 305 m spherical reflector at Arecibo was transmitting pulses coherently on 46.8 MHz. The bandwidth of the echoes was less than 10 Hz. The so-called decay line due to the parametric decay instability was expected at a frequency lower by about 300 Hz but it was not observed. Density variations caused by the ponderomotive force resulting from the standing wave pattern at 5. 1 MHz were tentatively invoked to explain the observations. Poorly understood aspects of previous analogous observations with the 430 MHz radar can be similarly explained.application/pdfenginfo:eu-repo/semantics/restrictedAccessRadarIonosphereEchoesPlasmainfo:eu-repo/semantics/articlehttp://purl.org/pe-repo/ocde/ford#1.05.01Journal of Geophysical Research: Space Physicshttps://doi.org/10.1029/JA088iA03p02083