Polar Scientists Explain 20 Year Mystery Behind Magnetospheric Radio Waves

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Polar Scientists Explain 20 Year Mystery Behind
Magnetospheric Radio Waves
In all planetary magnetospheres, hot plasmas tend
to be accompanied by radio waves. Every time we
see hot plasma we see broadband electrostatic
noise.
Theories of every sort were proposed to explain
the source of the radio waves, but none of the
theories completely fit the observations.
We now know why the theories dont fit these
were not radio waves.

• MEASUREMENTS
• Pioneering radio receivers with multiple
  antennas and high-speed digital electronics
  enabled Polar scientists to break through the
  barrier in understanding the origin of this
  broadband electrostatic noise.

Called Electron Phase Space Holes, bubbles
flowing in the tenuous gas of space were creating
the electrical signals
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Polar Scientists Explain 20 Year Mystery Behind
Magnetospheric Radio Waves

• OBSERVATIONS
• The radio noise could be resolved as bubbles
  (particle depletions) and observed to flow from
  one spacecraft antenna to the next.
• Each bubble represents plasma that has lost some
  of its electrons. Normally nature would
  immediately replenish the electrons, but the
  bubbles move so fast that nature does not have
  time to react.

• INTERPRETATION
• Like the discovery that living matter is
  composed of cells, we now know that hot plasmas
  have a universal feature heretofore unknown.

Called Electron Phase Space Holes, bubbles
flowing in the tenuous gas of space were creating
the electrical signals

• IMPLICATIONS
• By understanding that electrical bubbles, not
  radio waves, are universally present in hot
  plasmas, conflicting ideas about plasma transport
  and acceleration processes can be resolved.

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POLARs new weather map aurora display
The Iowa POLAR Auroral Imaging Team has developed
a new auroral display expected to be popular with
news and weather programs
Aurora data translated to U.S. centered weather
map view
Actual view from the spacecraft
Automatically generated and downloadable from a
web site, the images would be readily available
for inclusion in television broadcasts about
extreme solar-terrestrial events.
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POLARs new weather map aurora display
The display is always useful for Alaska and
northern latitude countries. When will it be
useful for the mid- to low-latitude states?
Actual view from the spacecraft
The overall structure of the aurora is driven by
magnetospheric processes. Thus the aurora tends
to form an oval which does not co-rotate with the
Earth. Rather, the continents rotate relative to
the aurora. The aurora usually crosses Alaska,
central Canada and northern Scandinavia. The
oval extends to lower latitudes on the nightside
and, since auroral events tend to occur as a
result of energetic particle injections towards
the Earth from the distant magnetotail, the
nightside of the Earth is frequently where the
action is. The most intense, unusual events are
due to particle injections deep into the
magnetosphere which then produce auroras over the
mid- to low-latitude states.
Thus, for auroral viewing at lower latitudes in
the U.S., the U.S. should be rotating across the
nightside during the hours of an extreme
solar-terrestrial event.
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POLARs new weather map aurora display
View for U.S.
Notice that since the U.S. was rotating through
the nightside at the time of the April 17, 1999
magnetic storm, it was in an ideal position to
view the most intense portion of the auroral
oval. At the same time instead of its normal
position over Alaska, the aurora was south of the
Alaska southern coast. Meanwhile, the aurora
just touched the northern extent of Europe.
View for Alaska
View for Europe
Actual view
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POLARs new weather map aurora display
This immediately recognizable format along
with accompanying information on the storms
progression and possible impact to ground systems
should help news organizations make our space
weather outreach efforts more accessible to
ordinary consumers.
Views of interest to specific regions of the
country would be available.
Louis Frank and John Sigwarth of the University
of Iowa will work with the POLAR project office
and GSFC PAO to develop an outreach package and
make these images readily available to news and
weather sources for interesting solar-terrestrial
events.