Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation
Russian Academy of Sciences
( founded in 1939 )
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Laboratory for Physics and modeling of the ionosphere: The experimental base of the investigations

 
  The experimental base of the investigations is the topside sounding data obtained on board of the Intercosmos-19 and Cosmos-1809 satellites. The Intercosmos-19 satellite was active during the high solar activity period from March 1979 to February 1981. It carried on board the following scientific payload: satellite ionospheric station for radio sounding of ionosphere (IS-338) and apparatus for the measurements of low-frequency electromagnetic field (VLF-2ME), electric component of high-frequency field (AHF-2K), electron temperature (KM-3), and spectrometer of photoelectrons (SF3-M). The Intercosmos-19 characteristics are given in the Table.

Parameter Интеркосмос-19 Космос-1809
Period of active processing from February, 1979 till February, 1981 from February, 1986 till December, 1990
Orbit Heights 500-1000 km ~1000 km
Orbit Inclination 74° 80°
Period between sounding 8 s, 16 s, 32 s, 64 s 16 s, 32 s
Duration of one telemetric data record ~15 m, 1 h, 2 h, 17 h 1 h, 2 h


The Cosmos-1809 satellite was launched on December 18, 1986 and failed on May 23, 1993. The scientific apparatus consisted of topside radiosound (IS-338) and set of the instruments for the measurements of the local parameters of the space plasma: low-frequency electromagnetic field (VLF-2ME), quasistationary electric field (DCEF), electric component of high-frequency field (AHF-2K), electron density and its irregularities (inhomogeneities) (IZ-2), electron temperature (KM-9), mass-spectrometer (NAM-4) and spectrometer of photoelectrons (SF-EM).

The N(h)-profiles of the electron density in the topside ionosphere were calculated from the ionograms obtained by means of IS-338. The example of such ionogram obtained on board of the Intercosmos-19 on November 28, 1979 is shown in Figure 1.

Figure 1. Ionogram obtained from topside sounding onboard Intercosmos-19

Ionogram


Figure 2. N(h)-profile of the mid-latitude ionosphere


N(h)-profile of the mid-latitude ionosphere


The N(h)-profile of the topside ionosphere calculated from this ionogram is shown in Figure 2. It is a typical profile for the daytime mid-latitude ionosphere for high solar activity.