Measurement of characteristics of MF radio wave propagation in the ionosphere by the S-310-33 rocket experiment

The electron density in the lower ionosphere is very interesting because it affects the MF radio wave propagation. In order to investigate the electron density profile in the lower ionosphere, we load the S-310-33 rocket with the medium frequency receiver (MFR), and the S-310-33 rocket experiment was carried out. The MFR observed the radio wave intensities at 238 kHz and 873 kHz in the lower ionosphere. The electron density in the lower ionosphere is estimated by the MF absorption method. The MF absorption method is developed to estimate the electron density by comparing the observed wave intensity with that calculated with the full wave method. In the profile of the radio wave intensities observed by the MFR the radio wave is suddenly absorbed at an altitude of from 88.5 km to 89.5 km. The electron density is estimated to increase suddenly at this altitude.