Sudden Impulses of Solar Wind Dynamic Pressure studied by means of SuperDARN radars

The Super Dual Auroral Radar Network (SuperDARN) has been
developed in the last 10 years for the study of the high latitude
ionosphere in the framework of Solar-Terrestrial Relations and of the
investigation of the near Earth environment. SuperDARN consists of two
longitudinal chains, in the Northern and Southern hemispheres,
comprising respectively of 11 and 7 HF coherent radars, that work
sincronously and continuously. The main objective of SuperDARN is the
constant monitoring of the instantaneous configuration of large-scale
convection electric field on the E and F regions of the ionosphere in
the auroral zones and the polar caps, because these phenomena are
directly related to the variations on the dynamics of the Solar Wind
and the coupling between the Solar Wind and the Earth's magnetosphere.
An important factor which influences the energy transfer between the
Solar Wind, the magnetosphere and the Earth's ionosphere is the Solar
Wind Dynamic Pressure: during abrupt and strong variations of such
pressure, the cross-polar-cap-potential in the ionosphere can increase
of about 100% or more. The dynamics of the interaction and the
possible connections with concurrent variations of the Interplanetary
Magnetic Field (IMF) are not fully understood yet. To better classify
and study these events, we have built a database of 420 Sudden
Impulses of Solar Wind Dynamic Pressure (SI), i.e. strong increases/
decreases of the Solar Wind Dynamic Pressure, with a very fast rise/
fall time (few minutes) and with a duration of the new pressure state
of at least 30 minutes, between January 1998 and December 2004. Along
with plasma and IMF data from the Solar Wind (ACE and WIND
spacecraft), the database includes AE index and the SuperDARN data (in
the pre-processed "fit" format) in two-hour windows centered on each
event time.