Figure 1: The Earth magnetosphere - animated view from space
|
Geomagnetic field
lines can guide energetic charged particles (electrons and protons) from
magnetosphere or magnetosheath (Figure 1) down to Earth's atmosphere. Precipitating
particles loose their energy via collisions with the neutral particles
and ionize them at approximately the same altitude range (100 to 600 km
altitude) than solar UV radiation when creating the ionosphere. In addition,
some of the atmospheric constituents are excited to higher energy levels:
this can lead to emission of auroral light. Most of this activity occur
within auroral oval. The auroral oval is a "fiktiv oval" around the Earths
geomagnetic poles (Figure 2). It can be seen as a propabilty to see the aurora (red represents a high probility).
Figure 2 illustrates that at midlatitudes one expects a low propability to see aurora.
An often used classification divides the aurora two forms: i) discrete and ii) diffuse precipitation. In addition, while the nightside auroras reflect the dynamics of the magnetotail, dayside precipitation relates more directly to solar wind parameters. Auroras during magnetospheric substorms and, especially, the great auroras during magnetospheric storms can create extremely impressive spectacles, and it is no wonder that auroras have entered into the folklore of peoples living at high latitudes, e.g. Eskimos, Samish and South-American Indians. The newest geomagnetic
parameters are shown below (update every 10 minutes). Via "click" you are
able to access the american NOOA internet pages. Solar X-rays are influencing
the ionopheres of the planetes - also Earth ionosphere. They are a key
parameter in the modern space and aurora research. The amplitude of the
gemagnetic field B is a criteria for aurora determination and forcasting.
If you wish to take some photograph of auroral displays (Figure 3) you shall understand some more basics about the auroral phenomena. A very comprehensiv paper was written about the AURORA by Larry Combs and Rodney Viereck, 1996 (download here as Adope PDF file - click to open the document). Now you might ask how did
I got involved with the northerlights?
From my early childhood I (Michael A. Danielides) was
interested in astronomy. As next step I started studying
physics at the Free University of
Berlin in 1991. It was like coming closer to fulfil myself a dream
of 'touching the sky'. However, this dream was rapidly modified in the moment I
observed my first aurora in early spring 1993, during a winter hiking trip in northern
Scandinavian via snow shoes and tent ... You have to understand in the far,
almost empty and totally frozen-in last wilderness of northern Europe the
aurora can touch a mans´ soul as nothing else could do! So I found my way to
investigate the aurora. First just as an amateur (taking nice photographs) and
since 1997 as post-graduate student at the
University of Oulu. Since that
time I have written various scientific
papers and reports.
By the way: Feel free to read, comment on them and give me any reply. Finally in 2005 I
received a PhD in space physics from the University of Oulu.
After a short 'research holiday' in industry I was so lucky to be accepted as an
Post Doctoral Fellow at the Geophysical Institut
/ University of Alaska Fairbanks. Together
with Prof. Dirk Lummerzheim
and Prof. Antonious Otto
we are studying the physics of
vertical and horizontal neutral winds above auroral filaments located in the
auroral oval. Selected images from films, I exposed since 1993 all around in north scandinavia:
|
|
DISCLAIMER: In the past people have been asking frequently to buy some enlarged colour copies of those auroral pictures. So far the policy has been not to sell any of the images. Remember: Those pictures above are only in internet quality. However, also they are under copyright and copying and publishing them is prohibited without permission, since they are reserved for publications in popular scientific journals or for educational purposes when proper citied (e.g. lectures for student at schools or universities). Commercial education purposes are excluded! For further information please contact: Michael A. Danielides.
|
(c) by Michael A. Danielides, 1999 - 2009
Last updated on Februray 21st, 2009.
To the webmaster
!