SPACE WEATHER - MSSL SPACE
PLASMA GROUP
The
Sun does not only emit heat and light. Every second a million tonnes of hot
plasma, electrons and ions, escape the Sun?s gravity. This solar wind buffets
any obstacles, including Earth?s magnetic shield, but even this is leaky and
lets electrons and ions through to cause the aurora and problems for
satellites. Without solar wind the Earth would be like a bar magnet in space.
With solar wind, the magnetic field is compressed like a balloon on the Sun
side and dragged out into an invisible comet-like tail behind. Conditions
depend on the 11-year solar activity cycle, the 27-day solar rotation and the
interplanetary conditions. Near solar maximum, as in 2000, there are more
?coronal mass? ejections from the Sun, tens of billions of tonnes at a time,
which disrupt the constant flow of the solar wind. Also there are more flares
which hurl faster particles Earthwards. Space weather is about all these
effects - and their influence on the Earth and mankind?s technological systems.
The Sun Earth Connection: Huge eruptions from the sun, can send billions
of tonnes of plasma towards the Earth.
The
group are active in several areas of the application of space plasma physics.
These include helping to define ESA's future space weather monitoring programme
as part of a contract led by satellite industry. In addition it has just been
announced that MSSL are starting two studies funded by the satellite insurance
industry, as part of the Tsunami initiative, to examine the effects of space
weather on satellites. The first involves the development of a "black
box" detector to be carried by future commercial satellites. This will add
much needed data to what are currently sparse records of the radiation
environment near the Earth. The second study will involve the categorisation of
the magnetospheric environment at times of satellite anomalies. This will pave
the way for early work on predicting periods that may be hazardous to
satellites.
We
are studying the science behind space weather in our main stream research,
using data from Polar, Geotail, Wind, STRV-1a and CRRES - and the
exciting Cluster satellite quartet will reveal the underlying small scale
processes for the first time.
Page maintained by Andrew Coates and
Gary Abel
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