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Ann. Geophys., 25, 661-673, 2007
www.ann-geophys.net/25/661/2007/
© European Geosciences Union 2007
TRANS4: a new coupled electron/proton transport code – comparison to observations above Svalbard using ESR, DMSP and optical measurements
C. Simon1, J. Lilensten1, J. Moen2,3, J. M. Holmes3, Y. Ogawa4, K. Oksavik5, and W. F. Denig6,*
1Laboratoire de Planétologie de Grenoble, Grenoble, France
2Plasma and Space Physics Group, Department of Physics, University of Oslo, Norway
3Department of Arctic Geophysics, University Centre in Svalbard (UNIS), Longyearbyen, Norway
4Solar-Terrestrial Environment Laboratory, Nagoya University, Japan
5The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
6Space Vehicles Directorate, Air Force Research Laboratory, Hanscom AFB, MA, USA
*now at: National Geophysical Data Center, NOAA, Boulder, CO, USA
Abstract. We present for the first time a numerical kinetic/fluid code for the
ionosphere coupling proton and electron effects. It solves the fluid
transport equations up to the eighth moment, and the kinetic equations for
suprathermal particles. Its new feature is that for the latter, both
electrons and protons are taken into account, while the preceding codes
(TRANSCAR) only considered electrons. Thus it is now possible to compute in a
single run the electron and ion densities due to proton precipitation. This
code is successfully applied to a multi-instrumental data set recorded on 22
January 2004. We make use of measurements from the following set of
instruments: the Defence Meteorological Satellite Program (DMSP) F-13
measures the precipitating particle fluxes, the EISCAT Svalbard Radar (ESR)
measures the ionospheric parameters, the thermospheric oxygen lines are
measured by an all-sky camera and the Hα line is given by an
Ebert-Fastie spectrometer located at Ny-Ålesund. We show that the code
computes the Hα spectral line profile with an excellent agreement
with observations, providing some complementary information on the physical
state of the atmosphere. We also show the relative effects of protons and
electrons as to the electron densities. Computed electron densities are
finally compared to the direct ESR measurements.
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