Abstract Some peculiarities of the source region of proton precipitations and electromagnetic ion-cyclotron waves on the dayside during magnetospheric compression are considered. Flashes of proton emission observed by the IMAGE satellite in the dayside sector equatorwards from the proton aurora oval are used to localize this region. The data from the LANL geostationary satellites, the projections of which during magnetospheric compression were within the proton emission flash, made it possible to find that the source region of the proton precipitations is usually located outside the plasmasphere. In periods of increased geomagnetic activity, this region is located closer to the Earth. Using NOAA satellite data, it is shown that in the dayside outer magnetosphere, precipitations of energetic protons with relatively low intensity are observed prior to magnetospheric compression. This fact shows that the conditions for the development of ion-cyclotron instability are fulfilled there. Magnetospheric compression leads to a sharp increase in the instability increment and, as a consequence, to a sharp growth in the fluxes of precipitating protons, exceeding the level needed for the registration of proton auroras on board the IMAGE satellite.
Some characteristics of the magnetospheric source of dayside subaroural proton precipitations during magnetospheric compression
Cosmic Research ; 53 , 1 ; 80-87
2015-01-01
8 pages
Article (Journal)
Electronic Resource
English
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