Earth’s magnetic field acts like a cosmic magnet, capturing charged particles from space. These particles gather in a doughnut-shaped zone around our planet, called the ring current.
This ring current is essential in how Earth deals with space weather. Space weather can impact technologies we rely on, like satellites and power grids. However, there’s still a lot we don’t know about this phenomenon.
Nasa is launching the STORIE mission (Storm Time O+ Ring current Imaging Evolution) in May aboard a SpaceX rocket. This mission aims to give scientists a deeper look at the ring current. Once installed on the International Space Station, STORIE will observe the ring current from inside out, helping researchers understand how it behaves and what it’s made of.
“These particles have significant impacts during space weather events,” says Alex Glocer, the mission’s lead at NASA’s Goddard Space Flight Center. “We want to learn about their origins and how they accumulate.”
The ring current can change dramatically, especially during solar storms. Unlike the stable Van Allen radiation belts, the ring current can expand and contract quickly. This ebb and flow affects electrical currents on Earth, potentially disrupting power lines and pipelines. It can also lead to issues with satellites, causing them to deorbit sooner than expected.
Studying the ring current is a challenge because the particles are invisible. Instead of using cameras, STORIE will look for the glow of energetic neutral atoms, or ENAs. These atoms are formed when charged particles escape by stealing an electron from Earth’s upper atmosphere.
“Once they become neutral, they are free from Earth’s magnetic grip,” Glocer explains. “They can fly off in any direction.”
By measuring the speed and direction of these ENAs, STORIE could reveal where the ring current’s particles come from. Are they from the solar wind or from Earth itself?
The team is particularly interested in positively charged oxygen atoms (O+). If STORIE detects a lot of these, it suggests the ring current is mainly supplied by Earth’s atmosphere.
Another key question is how the charged particles build up. Glocer likens it to filling a lake: does it happen steadily like a waterfall, or in bursts like raindrops?
Earlier NASA missions like IMAGE and TWINS studied the ring current from above. However, their views were often obstructed by the Earth’s light. STORIE’s position will give a clearer picture, allowing scientists to see the trapped particles near the equator that previous missions missed.
Some brief rocket experiments have offered glimpses of the ring current, but they could only observe for a short time. STORIE will construct a detailed view of the ring current every 90 minutes as the space station orbits.
During its six-month mission, STORIE will track changes in the ring current over time, providing insights into how it responds during solar storms versus quieter periods. This knowledge can enhance our predictions of space weather and help reduce its effects on our essential technologies.
For more about STORIE and its mission objectives, visit NASA’s Space Weather page.
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Earth's Magnetic Field, Goddard Space Flight Center, Heliophysics, Heliophysics Division, International Space Station (ISS), ISS Research, Magnetosphere, Space Weather, The Sun
