UI professor observes space weather/earth connection

May 31, 2000

University of Iowa physics professor Jack Scudder said today (Thursday, June 1) that an international team of physicists has significantly advanced mankind's understanding of the northern lights and related phenomena by making the first direct observations of the switch that permits energy to be transferred between the solar wind and the Earth.

Scudder, who spoke on behalf of his co-authors at a news conference at the spring meeting of the American Geophysical Union in Washington, D.C., noted that the naturally occurring switch for this energy transfer, known as "magnetic reconnection," is responsible for the aurora borealis and australis, as well as occasional interruptions in radio and satellite communications. He said that the outer layer of the Earth's magnetosphere generally behaves like a cocoon, shielding the Earth from reconnection, but that every once in a while a tear appears as a result of reconnection.

"Sometimes the solar wind creates tears in the cocoon, and charged particles and energy from the sun penetrate into the magnetosphere," said Scudder, who is principal investigator for the Hot Plasma Analyzer (HYDRA) on NASA's Polar spacecraft. "We have directly observed these tears for the first time using Polar.

"One of the most exciting things about the detection is finding that such small-scale structures really do exist in the precise sizes predicted 25 years ago. Some of these tears are extremely small -- on the order of one kilometer long," he said.

In the current investigation, scientists involved in the multi-satellite International Solar-Terrestrial Physics (ISTP) program identified two general areas where reconnection occurs. One region penetrated by Polar is 30,000 to 40,000 miles on the dayside of the cocoon, and the other (observed by the Geotail satellite) is inferred to be some 85,000 to 96,000 miles downwind of the Earth, on the night side of the planet and in the tail of the teardrop-shaped magnetosphere. ISTP is a collaborative study between NASA, the Japanese space agency (ISAS), and the European Space Agency (ESA), with contributions from Russia's Institute for Space Research (IKI) and many other international science institutions.

The observation of magnetic reconnection is of interest to physicists because it answers a half-century-old question surrounding the origin of the energy responsible for auroras and magnetic disturbances. On the dayside of the Earth, reconnection allows energy from the solar wind to enter the magnetosphere, that volume of magnetic fields surrounding the Earth that contains the Van Allen radiation belts. On the night side, reconnection permits the transfer of energy down to the Earth's atmosphere, but the whole sequence is started by reconnection on the dayside, as observed by Polar.

"Everything that happens regarding space weather happens through and because of these slits," Scudder said. "We're excited that the data clearly show the electrons jumping through these slits, doorways really, that open the Earth to these particles from space. The $64 question is what makes the tears possible. We'd like to see some more of them to know whether those already detected represent a general or an unusual picture of the switch."
To better define where the tears take place, Scudder has helped outline an entire NASA satellite mission. Dubbed BLAST (Boundary LAyer SnapshoT), it would carefully study these small, but crucial, intersections of the magnetic highways between the sun and the Earth. The investigation would be a collaborative effort between the University of California, Berkeley; UCLA; the University of Colorado and the University of Iowa. Additional information on reconnection and ISTP can be found on the web at: http://www-st.physics.uiowa.edu/www/html/press/video.html.

General News
University of Iowa
100 Old Public Library
Iowa City, IA 52242

University of Iowa

Related Solar Wind Articles from Brightsurf:

Wind beneath their wings: Albatrosses fine-tuned to wind conditions
A new study of albatrosses has found that wind plays a bigger role in their decision to take flight than previously thought, and due to their differences in body size, males and females differ in their response to wind.

New research deepens understanding of Earth's interaction with the solar wind
A team of scientists at PPPL and Princeton University has reproduced a process that occurs in space to deepen understanding of what happens when the Earth encounters the solar wind.

Hydropower plants to support solar and wind energy in West Africa
Study maps smart electricity mix composed of solar, wind and hydropower for West Africa -- regional cooperation can provide up to 60% reliable and clean electricity

Solar and wind energy sites mapped globally for the first time
Researchers at the University of Southampton have mapped the global locations of major renewable energy sites, providing a valuable resource to help assess their potential environmental impact.

New research helps explain why the solar wind is hotter than expected
When the sun expels plasma, the solar wind cools as it expands through space -- but not as much as the laws of physics would predict.

Solar wind samples suggest new physics of massive solar ejections
A new study led by the University of Hawai'i (UH) at Mānoa has helped refine understanding of the amount of hydrogen, helium and other elements present in violent outbursts from the Sun, and other types of solar 'wind,' a stream of ionized atoms ejected from the Sun.

Supporting structures of wind turbines contribute to wind farm blockage effect
Much about the aerodynamic effects of larger wind farms remains poorly understood.

Parker Solar Probe traces solar wind to its source on sun's surface: coronal holes
New data from the Parker Solar Probe, which got closer to the sun than any other spacecraft, allowed physicists to map the source of a major component of the solar wind that continually peppers Earth.

Closest-ever approach to the sun gives new insights into the solar wind
The Parker Solar Probe spacecraft, which has flown closer to the sun than any mission before, has found new evidence of the origins of the solar wind.

SwRI-built instrument confirms solar wind slows farther away from the Sun
Measurements taken by the Solar Wind Around Pluto (SWAP) instrument aboard NASA's New Horizons spacecraft are providing important new insights from some of the farthest reaches of space ever explored.

Read More: Solar Wind News and Solar Wind Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.