Abstract
In this study we take advantage of the slow, smooth rotation of the strong magnetic fields in interplanetary
magnetic clouds to identify transitions between particle precipitation/plasma convection
states of the magnetosphere and relate them unambiguously to the interplanetary conditions.
Focus is placed on magnetospheric states driven by the passage at Earth of the following
three magnetic clouds: August 12-13, 2000; May 20-21, 2005; and June 12-13, 2005. Interplanetary
field and plasma data were acquired by the Wind spacecraft. Plasma convection and
particle precipitation states are identified from passages of spacecraft DMSP F13 across the
northern hemisphere polar regions in approximate dusk–to–dawn orbits.
Emphasis is placed on the discriminating between different categories of plasma convection
cells and the corresponding particle precipitation and field Aligned current characteristics. Supplementary
information on the magnetospheric states is obtained both from magnetic field deflections
detected by the same satellite as it traverses systems of field-aligned currents as well as
from FUV (Far-UltraViolet) images and convection pattern obtained from spacecraft IMAGE
and SuperDARN radar network, respectively .
By this technique we are able to establish the correspondence between polar cap convection/-
precipitation states and parameters such as the (i) the orientation of the magnetic field in the
cloud as parametrized by the clock angle of the magnetic field in the magnetic cloud, (ii) the
IMF By and Bx polarities, and (iii) solar wind density/dynamic pressure. The conclusions extend
recent work in the area.