Cold Plasma Shield in Upper Atmosphere

The Earth's plasmasphere is an inner part of the magneteosphere. It is located just outside the upper ionosphere located in Earth's atmosphere. It is a region of dense, cold plasma that surrounds the Earth. Although plasma is found throughout the magnetosphere, the plasmasphere usually contains the coldest plasma. _NASA

Cold plasma has been well-hidden. Space physicists have long lacked clues to how much of this electrically charged gas exists tens of thousands of miles above Earth and how the stuff may impact our planet's interaction with the sun. Now, a new method developed by Swedish researchers makes cold plasma measurable and reveals significantly more cold, charged ions in Earth's upper altitudes than previously imagined.

...The low-energy ions are created in the ionosphere, a region of the upper atmosphere where solar energy can sweep electrons away from molecules, leaving atoms of elements like hydrogen and oxygen with positive charges. Actually detecting these ions at high altitudes has been extremely difficult.

Now that has changed, making it apparent that low-energy ions abound in the distant reaches where Earth's atmosphere gives way to outer space. Researchers knew the ions were present at altitudes of about 100 kilometers (60 miles), but André and his colleague Chris Cully looked much higher, between 20,000 and 100,000 km (12,400 to 60,000 mi). While the concentration of the previously hidden cold ions varies, about 50 to 70 percent of the time the particles make up most of the mass of great swaths of space, according to the researchers' satellite measurements and calculations. And, in some high-altitude zones, low-energy ions dominate nearly all of the time. Even at altitudes around 100,000 km — about a third of the distance to the moon — the team detected these previously elusive low-energy ions. _AGU

Earth is losing about 1 kg of atmosphere per second to near space, much of that in the form of cold plasma. But the plasma does not necessarily disappear. Rather, much of it stays in orbit, continuing to interact with the planet's magnetic field and with the solar wind.

For decades, space physicists have struggled to accurately detect low-energy ions and determine how much of the material is leaving our atmosphere. The satellite André works on, one of four European Space Agency CLUSTER spacecraft, is equipped with a detector with thin wire arms that measures the electric field between them as the satellite rotates.

But, when the scientists gathered data from their detectors, two mysterious trends appeared. Strong electric fields turned up in unexpected regions of space. And as the spacecraft rotated, measurements of the electric field didn’t fluctuate in the smoothly changing manner that André expected.

...As scientists use the new measurement method to map cold plasma around Earth, they could discover more about how hot and cold plasmas interact during space storms and other events, deepening researchers' understanding of space weather, André said.

The new measurements indicate that about a kilogram (two pounds) of cold plasma escapes from Earth's atmosphere every second, André said. Knowing that rate of loss for Earth may help scientists better reconstruct what became of the atmosphere of Mars, which is thought to once have been denser and more similar to Earth’s. The new cold plasma results might also help researchers explain atmospheric traits of other planets and moons, André suggested.

And closer to home, if scientists could develop more accurate space weather forecasts, they could save satellites from being blinded or destroyed, and better warn space station astronauts and airlines of danger from high-energy radiation. While low-energy ions are not responsible for the damage caused by space weather, they do influence that weather. André compared the swaths of ions to, say, a low-pressure area in our familiar, down-to-Earth weather — as opposed to a harmful storm. It is a key player, even if it doesn’t cause the damage itself. "You may want to know where the low-pressure area is, to predict a storm,” André noted. _DailyGalaxy

The cloud of cold plasma circling Earth acts as both a shield and as an interface. Some of the mysterious energetic activity that occurs at the atmospheric boundaries with space no doubt involve fluctuations in the cold plasma cloud.

Scientists are rushing to adjust their computer models of space weather, as a result of these new satellite data findings. And it is possible that we may find that planetary weather is also affected in some way by this mysterious cloud of cold plasma. Watch and learn.