The Journey of Flight.pdf - Valkyrie Cadet

Chapter Chapter Chapter 24 24 - - Space Space Environment
Environment
in the behavior of the ionosphere. The normal rhythm of nights and days also affects the behavior of
the ionosphere. SlDs, for example, will produce excess electrons in the atmosphere, and these will
absorb radio waves. The magnetic forces of the Earth also have an effect on the behavior of the ionosphere.
It is the interaction of solar radiation and the Earth’s magnetism that produces the aurora
borealis and aurora australis. Particles traveling swiftly toward the Earth’s two magnetic poles produce
these glowing displays.
The ionosphere is generally regarded as extending to more than 250 miles above Earth’s surface,
well beyond the altitude where most of the atmosphere exists. One name applied to space beyond the
Earth’s atmosphere is exosphere (outside sphere). The ionosphere blends into the exosphere, which
must not be considered a dead vacuum. It contains atomic and subatomic particles. This is especially
true of the Van Allen belts.
Magnetosphere Magnetosphere and and Solar Solar W WWind
W ind
Before studying the Van Allen belts in detail, a look at the Earth’s magnetosphere and the effects
upon it by the solar wind is essential. This is due to the Van Allen belts being closely related to the
behavior of the magnetosphere.
Magnetosphere. The region of the Earth’s atmosphere where ionized gas plays a big part in the
dynamics of the atmosphere and where the geomagnetic field plays an important role is called the
magnetosphere. The magnetosphere begins about 217 miles above the Earth’s surface and extends 10
or 15 Earth radii to
the boundary between
the atmosphere
and the interplanetary
plasma.
Earth, like most
other planetary and
stellar bodies, is surrounded
by a tremendous
magnetic field.
Remember the experiment
where a bar
magnet is placed beneath
a piece of paper
on which there are
iron filings? If the
magnet is close
enough for its magnetic
field to affect
the filings, they take
on the shape of the
Regions of the Magnetosphere
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