 |
| Titel |
Deducing spatial properties of auroral primary particle distributions from ground-based optical imaging. |
| VerfasserIn |
Katarina Axelsson, Tima Sergienko, Ingrid Sandahl, Urban Brändström |
| Konferenz |
EGU General Assembly 2011
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250045982
|
|
|
|
|
|
| Zusammenfassung |
| The distribution of particles impinging on the upper atmosphere
constitutes the most important link between magnetospheric processes
and the optical aurora. Particle measurements from satellites and
sounding rockets give the most exact information about the primary
particle distribution, but they are only able to provide snapshots and
statistical results. With ground-based imaging, on the other hand, it
is possible to record the aurora over a large area for an extended
period of time, and it is therefore of great interest to be able to
deduce properties of primary particle distributions from optical data.
So far, the most successful methods have relied on different emission
intensity ratios, but these methods only work well for field-aligned
measurements. This is obviously a severe limitation. In this paper we
discuss ways to obtain information on primary particles away from
magnetic zenith. In a recent study we have used images of the auroral
red and green line emissions obtained from different ALIS stations to
estimate the maximum deviation from magnetic zenith of the measurement
direction for which the results are reliable. Taking the altitude
difference between the red and green line emission peaks (about 100
km) into account we find that the green to red intensity can be used
to reconstruct auroral electron parameters for directions up to 30
degrees from magnetic zenith. Implications for magnetospheric
processes in selected cases, as well as interpretation problems, will
be discussed. |
|
|
|
|
|
|