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The
Questions |
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LASCO, in conjunction with the other instruments aboard SOHO, is able
to assist in addressing some of the fundamental questions about the solar
corona and this is reflected in the research being done. Why is the corona so hot?
The
coronal plasma is sandwiched between cold space and the relatively cool solar
surface, yet is maintained at a temperature of several million Kelvin without
any obvious energy source.
How is the solar wind accelerated?
There
is a constant outflow of plasma from the Sun. Particles travelling at speeds
of up to 700 km/s (depending on the magnetic structures at their source) are
being driven to the very edge of the solar-system. The mechanism behind this
acceleration and the location at which it occurs is not fully understood.
What causes coronal mass ejections?
Bubbles
of plasma are ejected into the corona reasonably frequently, something like
once per day, and become more frequent at solar maximum. They are often
associated with surface phenomenon
such as erupting filaments but the exact relationship isn't fully understood.
Large amounts of kinetic energy are involved with up to 10^13 Kg of material
being accelerated to around 400 km/s.
How does the global corona evolve?
LASCO
is able to study the effects of emerging magnetic flux at the solar surface
on the large scale corona at heights well beyond that previous available. It
is already clear that the fairly stable structures seen at solar minimum are
becoming more complex in only the first year or so of the increase towards
solar maximum.
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