There are 4 main topics we focus on:
1. Conjugate imaging of auroral phenomena
Aurora generally occurs simultaneously in the northern and southern
polar regions at locations that are connected (i.e., conjugated) by closed geomagnetic
field lines with footpoints in both hemispheres.
Such a connection predicts a symmetric temporal behaviour and spatial location.
Simultaneous space-based observations of the same auroral
feature in both hemispheres can provide evidence or disprove
the expected conjugate behavior. Only twice have scientists had the possibility to study
auroral from two spacecrafts that image the aurora in the
northern and southern hemisphere at the same time. In the 80s
Viking and Dynamic Explorer 1 offered this opportunity and now
(2001-2003) the two missions: IMAGE and Polar (POLAR_IMAGE_orbit.jpg).
These unique images have been used to study:
A. Asymmetries of the auroral oval and substorm locations in the
B. Asymmetries of the dayside reconnection spot, i.e., the footprint of
the energy and momentum transfer from the solar wind to the Earth's
C. Transpolar arcs or theta aurora. Are they occurring in both
hemispheres simultaneously or only in one?
2. The ring current in the magnetosphere and proton precipitation
Does the intenistity of global proton precipitation follow the increase and decrease of
the large current system surrounding the Earth at 2-5 Re, i.e., the ring current.
3. Energy and momentum transport from the Sun (solar wind) to the near Earth system.
Reconnection rate is a measure of how fast energy and momentum are transferred
from the solar wind into the magnetosphere.
Combined study using IMAGE from space and EISCAT from Tromsø and Svalbard to study
the reconnection rate.
4. Geocoronal imaging and hydrogen density profiles
The Lyman alpha emission (121.6 nm) from the Sun brighten up the neutral cold
hydrogen around the Earth. This is called the geocorona and its brightness
depends both on the source (the Sun) and the density of hydrogen around the Earth.
Long time series of such data have been used to develop a model of the
hydrogen density surrounding the Earth.