Slide show made by Thomas Leyser for the observatory day 2016-04-28


The Swedish Institute of Space Physics operates ionosondes in Lycksele and Uppsala.

Ionosondes are simple radars that use radio pulses to detect and range the plasma density in the bottomside ionosphere.

The frequency of the vertically transmitted wave determines the plasma density from which the pulse is relfected in the ionosphere. The time delay between transmission and reception of the reflected pulse on the ground is a measure of the height of the ionospheric layer from which the pulse was relfected. In this way the height of a specific plasma density is obtained.

An ionosonde operates by stepping the frequency of the pulses from say 1 to 20 MHz, thereby producing a map of the bottomside ionosphere. The data from such a frequency sweep is presented as the time-of-flight (virtual height) versus the transmitted frequency (the plasma frequency which is related to the plasma density). The result is an ionogram.

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Responsible scientist: Thomas Leyser, thomas.leyser*irf.se
Updated: 2011-09-01, webmaster*irf.se