The report «Some aspects of determination of electron concentration in the plasmasphere based on whistlers recorded in Kamchatka» has been presented at the Conference «Physics of Plasma in the Solar System»

The event was organized and hold at Space Research Institute of the Russian Academy of Sciences. About 400 people participated in it.

The authors of the presentation are the Leading Researcher of IKIR FEB RAS, Dr. Sci. (Phys.-Math.) Parovik Roman Ivanovich and the Scientific Secretary of IKIR FEB RAS, Marchenko Ludmila Sergeevna.

Electromagnetic waves of VLF range, propagating along the Earth magnetic field, are called whistlers. It is known that based on whistlers, it is possible to estimate plasmasphere electron concentration when the nose frequency and the group absolute delay time (limiting variance) are available. Moreover, at mid latitudes, where Kamchatka is located, whistlers are recorded at the range lower than the nose frequency. To determine the delay time, it is necessary to know the initiating atmospheric (lightning discharge) that is almost impossible to do on a spectrogram. Thus, methods, based on whistler trace extrapolation from an available spectrum portion, are more frequently used.

The researchers used linear extrapolation method of dynamic spectra of the whistlers recorded in Kamchatka to estimate the nose frequency. When the nose frequency is known, it is possible to estimate plasmasphere electron concentration by Park method, for example, within the model of diffusion equilibrium DE1.

A software package, realizing the algorithms described above, was developed. Nose frequency and limiting variance were estimated for a whistler series recorded in Kamchatka, on the basis of which electron concentration in the plasmasphere was calculated. It is interesting to note that electron concentration at the height of 1000 km, obtained by the mentioned method, is close to electron concentration value obtained by using the International Reference Ionosphere (IRI) model. The coordinates for IRI were selected so that they were as close to Karymshina observation site in Kamchatka as possible.

The work was supported by the State Task of IKIR FEB RAS (Reg. No. 124012300245-2). The data used in this work were obtained from the Shared Research Facility «North-Eatern Heliogeophysical Center» (SRF NEHC).