Parameters of ion kappa distribution at the equatorial plane at geocentric distances smaller than 15 RE and auroral oval mapping to the equatorial planeстатья
Дата последнего поиска статьи во внешних источниках: 4 мая 2020 г.
Аннотация:The improvement of the accuracy of the mapping of the auroral oval boundaries to the equatorial plane using method of morphological mapping requires the determination of the ion pressure distribution at low latitudes and at the equatorial plane. To obtain exact values of pressure it is necessary to take into account the contribution of particles with energies much larger than energies of thermal particles. Particle distribution functions in the collisionless magnetospheric plasma are well approximated by kappa distributions. Kappa distributions have Maxwell core and power tails and characterize by three parameters: by density, core energy/temperature and value k, which characterize the spectra slope at energies much larger than thermal energies. Analyses of THEMIS mission observations permit to obtain averaged distribution of kappa parameters of ions at the equatorial plane on geocentric distances from 7 toll 15 RE. We obtain the radial and MLT dependences of kappa parameters. The using of obtained results for the qualification of auroral oval mapping is discussed.