Dynamic rayed aurora and enhanced ion-acoustic radar echoes
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https://hdl.handle.net/10037/551Date
2005-01-31Type
Journal articleTidsskriftartikkel
Peer reviewed
Author
Blixt, Erik Mårten; Ivchenko, N.; Hagfors, T.; Grydeland, Tom; Trondsen, T.S.; La Hoz, Cesar; Lanchester, B.S.; Løvhaug, Unni PiaAbstract
The generation mechanism for naturally enhanced
ion-acoustic echoes is still debated. One important issue is
how these enhancements are related to auroral activity. All
events of enhanced ion-acoustic echoes observed simultaneously
with the EISCAT Svalbard Radar (ESR) and with
high-resolution narrow field-of-view auroral imagers have
been collected and studied. Characteristic of all the events
is the appearance of very dynamic rayed aurora, and some
of the intrinsic features of these auroral displays are identified.
Several of these identified features are directly related
to the presence of low energy (10–100 eV) precipitating electrons
in addition to the higher energy population producing
most of the associated light. The low energy contribution is
vital for the formation of the enhanced ion-acoustic echoes.
We argue that this type of aurora is sufficient for the generation
of naturally enhanced ion-acoustic echoes. In one event
two imagers were used to observe the auroral rays simultaneously,
one from the radar site and one 7 km away. The data
from these imagers shows that the auroral rays and the strong
backscattering filaments (where the enhanced echoes are produced)
are located on the same field line, which is in contrast
to earlier statements in the litterature that they should be separated.
Publisher
European Geosciences UnionSeries
Annales Geophysicae 23(2005), pp 3-11Metadata
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