Within this magnetic comet tail other currents are driven by the motion of plasmas in the defining magnetic field, like
- the cross-tail current maintaining the elongated magnetic tail,
- magnetic field-aligned currents, coupling this tail currents and some of the magnetopause surface currents to the highly conduction upper atmosphere, and
- the ring currents, which are determined by plasma drift motion in the gradients and curvature of the closed dipole field.
- At the bottom end of the magnetospheric field-aligned current electric charges, and also electric fields created by the mapping of a general convection of magnetospheric fields imposed by the solar wind, set up a complicated system of ionospheric currents, which depends on both the initial driving fields, but also on the particular ionospheric conductivities created by the precipitation of energetic particles from the magnetosphere. Such ionospheric currents are referred to as auroral electrojets, and they couple back to the magnetospheric current sources via diverging currents at any ionospheric conductivity gradients. Depending on the importance and dominance of certain solar wind drivers this complicated coupled system of current sinks and sources can take a variety of complicated shapes, and even dynamic and short-lived structures. It can furthermore cover a wide range of longitudes and both high to medium latitudes, depending again on the strength and energy of the original solar wind drivers.
Another independent and strictly ionospheric current system at lower latitudes is coupled to plasma flow and related electric field structures around the almost horisontal portions of the magnetic dipole field close to the magnetic equator, the so called equatorial electrojets. These are rather depending on the variable solar radiation than the variable solar wind itself, which is the most important driver for the high-latitude ionospheric and all magnetospheric currents systems.
At any moment in time (also depending on the pre-history of each event) the entity of coupled magnetic and ionospheric current systems determines the geomagnetic environment for our man-made infrastructure. Any rapid changes in the current flow within this environment will generate strong electric fields, which in turn can generate strong induced currents in the ground and thus affect any extended conducting structures within our man-made infrastructure. Depending on the strength and variability of the solar wind, which drives the original magnetospheric current systems, the resulting coupled current systems in the upper atmosphere can be so large, change so rapidly and extend so far equatorward that major and crucial parts of our electrical (powerlines) and transport (pipelines and rails) infrastructure can be affected by such induced currents in the ground or within the infrastructure itself. The character of the current changes, and their temporal and spatial behaviour and extent, determines how dangerous - or rather how damaging – the induced current can impact on our infrastructure and its crucial nodal points such as joints, ends or, indeed, transformators.