"Space weather refers to
conditions on the Sun and in the space environment that can influence
the performance and reliability of space-borne and ground-based
technological systems..."-National
Space Weather Prediction Center (1995)
Strangely, it is not a well know fact
that the earth is being constantly subjected to an incredible amount of
electromagnetic radiation at any given point in time. This is due to
the phenomenon known as the solar wind. The Sun constantly radiates
matter and magnetic fields into space, bombarding planets in the solar
system, and while the most apparent effect of this is visible light
which can penetrate the atmosphere much of the other waves, especially
extreme-ultraviolet and x-rays, are dissipated into energy in the upper
atmosphere or are repulsed by the magnetosphere, the magnetic field
which surrounds the Earth . Evidence of this can be seen on Earth,
Saturn, Jupiter,
and several other astronomical bodies in the form of auroras which form
around the magnetic poles. Planets without magnetic poles, such as
Mars, also exhibit evidence of the solar wind. In the case of Mars,
this is seen in the stripping away of the outer atmosphere,
demonstrating the importance of magnetic fields.
The magnetic aspects of this constant
stream of energy are particularly interesting when considering
electronics and communications, which, when exposed to them, can suffer
signal degradation and reduced functionality. The Earth's surface has a
normal magnetic field strength, (in Teslas), of about 50uT, the
average solar wind about 6nT, and the average solar magnetic field is
about 100uT. Additionally, solar wind can cause geomagnetic storms
which form fields around 1uT in strength. These magnetic fields have
been shown to limit transistor operation and cause unexpected induction
in electrical systems, albeit seeming small in relation to physical
magnets, (e.g. refrigerator magnets have a field of about 7.5mT). The
most important difference between the two is that the effects of the
solar wind, the solar field, the geomagnetic field, and geomagnetic
storms are
global, and thus able to effect very large systems such as power grids,
and communications networks. After all, a performance drop of 1%
globally will still be an enormous reduction in efficiency.