The interplanetary magnetic field may cause large amplitude changes in the orbital inclinations of charged dust particles. In order to study this effect in the case of dust grains moving in 1:1 mean motion resonance with planet Jupiter, a simplified semi-analytical model is developed to reduce the full dynamics of the system to the terms containing the information of the secular evolution dominated by the Lorentz force. It was found that while the planet causes variations in all orbital elements, the influence of the magnetic field most heavily impacts the long-term evolution of the inclination and the longitude of the ascending node. The simplified secular-resonant model recreates the oscillations in these parameters very well in comparison to the full solution, despite neglecting the influence of the magnetic field on the other orbital parameters.

Superposed epoch analysis (SPEA) is commonly used to determine some basic structure in a collection of geophysical time series. The present study tries to analyze ionospheric Joule heating response at high latitudes, to the prevailing solar wind and IMF conditions on the basis of SPEA. Major geomagnetic storms (CME driven) over three consecutive solar cycles (SC 22, 23 and 24) have been selected. Ascending phase, solar maximum, and declining phase are investigated separately, for each solar cycle, to find out crucial controlling parameters for the generation of high-latitude ionospheric Joule heating. SPEA results show that, IMF parameters such as IMF By, IMF Bz, IMF clock angle and solar wind parameters such as dynamic pressure and proton density influence Joule heating production rate significantly. Meanwhile, the relentlessness of the other parameters such as IMFBt and solar wind bulk speed show that they have poor impact on Joule heating.

It is suggested that we are already in the weak solar cycles series since the start of cycle 23. The interplanetary magnetic filed and the solar wind speed and density are expected to drop considerably during the approaching second weak cycle number 24 and the following ones leading to inflation of the magnetosphere. The corona is also expected to cool down relative to normal cycles corona. A daily background coronal index is proposed. The mechanism of production of weak cycles is tied to the rapid rotation of the photospheric layer which is deeply rooted in the bottom of the convection zone. This rapid surface and subsurface rotation implies slower rotation of the tachocline. Slower dynamo rotation leads to reduction of the strength of the magnetic cycle. One of the very important sequences of the weak cycles, is the expected cooling of the Earths air and sea surface temperatures which would have negative effects on agriculture with increased drought-flood hazards. The reduction of solar UV flux can lead to the closure of the ozone hole on the long run.

A regression analysis was carried out between the ground-based geomagnetic data from the southern polar regions (above −55° corrected geomagnetic latitude) and the interplanetary magnetic field (IMF) components in the geocentric solar-magnetospheric co-ordinate system and solar wind (SW) parameters. Hourly mean values of the geomagnetic field horizontal components H and D from 20 Antarctic observatories and automatic stations of 1978–80 and 1983–84 were examined. Regression coefficients were used as geomagnetic perturbation vectors which were rotated 90° clockwise to plot the equivalent current vector patterns in the “corrected geomagnetic latitude-magnetic local time” co-ordinates. The results which are described in the paper reflect geomagnetic phenomena associated with the IMF and SW parameters for the austral summer season only (November, December, January, February). It was found that, in general, global characteristics of the ionospheric convection patterns agree well for both hemispheres. Geomagnetic variations, which are generated by the interaction of the SW plasma and frozen-in IMF with Earth's magnetosphere, represent three types of equivalent current systems: a) two-vortex system with transpolar current from nightside to dayside, controlled by the “quasi-viscous” interaction and southward IMF; b) zonal current system, controlled by the azimuthal IMF; and c) two-vortex system with transpolar current from noon to midnight controlled by the northward IMF. The southern polar cap (above −75°), which was more densely packed with automatic magnetometers than the northern cap, permit us to investigate the fine structure of the high-latitude current systems in detail.