Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Control of diurnal and seasonal variation of particle precipitation by regular changes of the interplanetary magnetic field

: Bremer, J.

Journal of Atmospheric and Terrestrial Physics 47 (1985), Nr.11, S.1123-8
ISSN: 0021-9169
Fraunhofer HHI ()
atmospheric elementary particle precipitation; interplanetary magnetic fields; magnetic storms; magnetosphere; solar wind; solar-terrestrial relationships; substorm precipitation; solar terrestrial relationships; ionosphere; solar wind-magnetosphere interaction; seasonal variation; particle precipitation; interplanetary magnetic field; dipole axis; earth's magnetic field; solar axis; vertical bz-component; solar-magnetospheric coordinate system; negative bzsm-values; spring; autumn; high energy particles; lower thermosphere; upper mesosphere; equinoxes; diurnal variations; imf sector structure

Systematic changes of the position of the dipole axis of the Earth's magnetic field with respect to the solar axis induce distinct daily and seasonal variations of the vertical BZ-component in the solar-magnetospheric coordinate system (BZSM). Depending on the direction of the interplanetary magnetic field (IMF) negative BZSM-values are produced in spring by T polarity and in autumn by A polarity, whereas in the diurnal variation, the lowest BZSM-values are calculated to occur near 23 UT for T, and near 11 UT for A polarity, respectively. In different ionospheric and geomagnetic parameters measured at high and mid-latitudes increased precipitation of high energy particles into the lower thermosphere and upper mesosphere has been detected during periods with negative BZSM-components. The seasonal variation of the parameters investigated, with maximum values near the equinoxes as well as part of their diurnal variations can thus be explained by particle precipitation being markedly controlled by the IMF sector structure.