Space Science MO&DA Programs - June 2000 - Page 1

SSIn all planetary magnetospheres, hot plasmas tend to be accompanied by radio waves.

Every time we see hot plasma we see broadband electrostatic noise.

Polar Scientists Explain 20 Year Mystery Behind Magnetospheric Radio Waves

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 don’t fit: these were not radio waves.

Called “Electron Phase Space Holes”, bubbles flowing in the tenuous

gas of space were creating the electrical

signals

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.

Space Science MO&DA Programs - June 2000 - Page 2

SSPolar Scientists Explain 20 Year Mystery

Behind Magnetospheric Radio Waves

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

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.

Called “Electron Phase Space Holes”, bubbles flowing in the tenuous

gas of space were creating the electrical

signals

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.

Space Science MO&DA Programs - June 2000 - Page 3

SS POLAR’s 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

Actual view from the spacecraft

Aurora data translated to U.S. centered “weather map” view

Automatically generated and downloadable from a web site, the images would be readily available for inclusion in television broadcasts about extreme solar-terrestrial events.

Space Science MO&DA Programs - June 2000 - Page 4

SS POLAR’s new “weather map aurora” display

Actual view from the spacecraft

The display is always useful for Alaska and northern latitude countries. When will it be useful for 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.

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.

Space Science MO&DA Programs - June 2000 - Page 5

SS POLAR’s new “weather map aurora” display

Actual viewView for Alaska View for Europe

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.

Space Science MO&DA Programs - June 2000 - Page 6

SS POLAR’s new “weather map aurora” display

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.

This immediately recognizable format – along with accompanying information on the storm’s 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.