Abstract: Incoherent Scatter Radar (ISR) is one of the most power ground based
methods to probe the ionosphere.  This has been made possible by a
well-developed statistical theory that enables estimation of ionospheric
state parameters in the D-, E-, and F-region ionosphere, given an
estimation of the autocorrelation function.  Other techniques have been
developed for ISR that enable estimation of other ionospheric
parameters, for example, estimation of E-region thermospheric winds.  We
will present two examples highlighting ISR capabilities in the auroral
zone: results from a long term investigation of E-region thermospheric
winds and examining D-region ionization enhancements from energetic
particle precipitation.

Auroral E-region thermospheric winds are thought to be driven by both
magnetospheric forcing from above and atmospheric forcing from below.
However, it remains unresolved what is the relative competition between
these forcing mechanisms, even during geomagnetically quiet intervals.
We present results from a statistical study of E-region neutral winds
collected by the Poker Flat Incoherent Scatter Radar (PFISR) near
Fairbanks, AK. PFISR has been collecting nearly continuous sampled data
since 2007 that is suitable for quantifying E-region neutral winds.
PFISR data correspond to one of the most comprehensive, regularly
sampled data sets to date. We present results from this 10+ year
database of the altitude-resolved monthly mean neutral wind profiles.
These radar-based observations are compared with general circulation
model results from previously published investigations to assess the
role of magnetospheric forcing on the E-region neutral winds.

Quantifying the loss of energetic particle precipitation (10-100 keV)
from the magnetosphere into the ionosphere is a difficult task, due to
the requirement of nearly conjugate and simultaneous observations along
a magnetic flux tube.  These energetic particles cause enhanced
ionization signatures in the lower E- and D-region ionosphere.  We
present results showing techniques for quantifying the precipitating
electron flux and average energy using models of D-region chemistry.  We
highlight some new capabilities from PFISR that enable these types of
observations.  We show a case study of the eventual application of these
methods, which are to use satellite-PFISR conjunctions to investigate
which wave-particle interactions cause significant energetic particle
precipitation.