2020/06/30 by Hans Wilschut, Wilschut, Hans W.
Physics and Astronomy · #Astro and Planetary Science #Earth and Planetary Astrophysics (astro-ph.EP) #FOS: Physical sciences #Instrumentation and Methods for Astrophysics (astro-ph.IM) #Ionosphere and magnetosphere dynamics #Magnetic confinement fusion research
paper · pdf · doi:10.48550/arxiv.2006.16927
openalex publication_date 2020/06/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The approximate frequency shift of a radar echo from a meteoroid is derived. The origin of head echos observed during trail formation are discussed by considering schematic models. The echo is either a reflection of the radar signal from thermalized electrons in the meteoroid trail or from the plasma electrons co-moving with the meteoroid itself. It is shown that in these opposite models the frequency shifts of the echo relative to the radar emitter frequency must be identical, even though the underlying physics differs. Calculations were made that give the echo frequency as function of time, allowing qualitative comparison with observations. Some typical observations show a conspicuous absence of negative frequency shifts in the head echo in forward scattering. Arguments are given that this can correspond to meteoroids with the co-moving plasma in front.