What is the highest critical frequency f0F2 ever recorded? Is anyone aware of a paper/reference or published ionogram for the reflection of 50 MHz (or higher) radio waves by the Ionosphere at incidence?
"At incidence, generally frequencies below 10 MHz are reflected but with active events frequencies up to 50 MHz and higher may also be reflected by the E-layer."
Thank you for your contributions in advance!
Best regards,
Alex
To clarify, I am not looking for a theoretical maximum; ANY paper with a f0F2 greater than 50 MHz that is either measured or inferred from electron density measurements are welcome. These would likely come from some short-lived solar event.
I tried a back-of-envelop calculation based on the peak density (~2e12 electrons/m3) given for daytime solar maximum conditions given in Table 1 from Anderson & Fuller-Rowell [1999].
http://solar-center.stanford.edu/SID/science/Ionosphere.pdf
Anderson, D. & Fuller-Rowell, T. The Ionosphere NOAA Space Environment Topics, 1999, 14
I used the approximation
fc =9xsqrt(nmF2)
where fc is the plasma frequency in Hz and nmF2 is the peak density in electrons per cubic cm [Schunk and Nagy, 2000]. Unfortunately this gives a value of 12.7 MHz, which does not agree with the range of maximum usable frequencies (21-42 MHz) given in the same table and assuming a rule of thumb that MUF is about 3 times fc.
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The variation of critical frequency of E layer over Chumphon, Thailand Poramintra Wongcharoen ; Prasert Kenpankho ; Kasemsuk Sepsirisuk ; Pornchai Supnithi ; Suthichai Noppanakeepong ; Somkiat Lerkvaranyu ; Takuya Tsugawa ; Tsutomu Nagatsuma 2013 IEEE International Conference on Space Science and Communication (IconSpace) Year: 2013 | Conference Paper | Publisher: IEEE
Thank you Fritz Caspers for these links: https://ieeexplore.ieee.org/author/37074098900
The variation of critical frequency of E layer over Chumphon, Thailand Poramintra Wongcharoen ; Prasert Kenpankho ; Kasemsuk Sepsirisuk ; Pornchai Supnithi ; Suthichai Noppanakeepong ; Somkiat Lerkvaranyu ; Takuya Tsugawa ; Tsutomu Nagatsuma 2013 IEEE International Conference on Space Science and Communication (IconSpace) Year: 2013 | Conference Paper | Publisher: IEEE
Conference Paper The variation of critical frequency of E layer over Chumphon, Thailand
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