May 23, 2018

Thanks to a technique developed by Amy Rager, a Catholic University doctoral candidate in physics, NASA scientists have discovered a new type of magnetic event in the near-Earth environment. The discovery was reported in the journal Nature earlier this month.

Rager is a researcher at NASA’s Goddard Space Flight Center in Greenbelt, Md., where she is part of a team of scientists working with NASA’s Magnetospheric Multiscale (MMS) spacecraft. She has been working at Goddard for 14 years, since she was a high school student in the Scientific and Engineering Student internship program, which was hosted at that time by Catholic University. She chose to pursue her doctorate at the University specifically because of the physics department’s close working relationship with NASA.

MMS uses four identical spacecraft flying in a pyramid formation to study magnetic reconnection around Earth in three dimensions. Because the spacecraft fly incredibly close together, they are able to observe phenomena no one has seen before. Furthermore, MMS’s instruments are designed to capture data at speeds a hundred times faster than previous missions.

Leveraging the design of one instrument, the Fast Plasma Investigation, Rager and her team were able to create a technique to interpolate the data, allowing them to read between the lines and gather extra data points.

“The key event of the paper (printed in Nature) happens in only 45 milliseconds. That would be one data point with the basic data,” said Rager. “But instead we can get six to seven data points in that region with this method, allowing us to better understand what is happening.”

With this new method, the MMS scientists are hopeful they can comb back through existing datasets to find more of these events, and potentially other unexpected discoveries as well.

This new data will help the team better understand magnetic reconnection, one of the most important processes in space that dissipates magnetic energy and propels charged particles, contributing to a dynamic space weather system.

Magnetic reconnection has been observed innumerable times in the magnetosphere — the magnetic environment around Earth — but usually under calm conditions. The new event occurred in a region called the magnetosheath, just outside the outer boundary of the magnetosphere, where the solar wind is extremely turbulent. Previously, scientists didn’t know if reconnection even could occur there, as the plasma is highly chaotic in that region. MMS found it does, but on scales much smaller than previous spacecraft could probe.

“In the plasma universe, there are two important phenomena: magnetic reconnection and turbulence,” said Tai Phan, a senior fellow at the University of California, Berkeley, and lead author on the paper. “This discovery bridges these two processes.”

Magnetic reconnection occurs throughout the universe, so when scientists learn about it around Earth — where it’s easiest for Earthlings to examine it — they can apply that information to other processes farther away.  The finding of reconnection in turbulence may help scientists understand the role magnetic reconnection plays in heating the inexplicably hot solar corona — the Sun’s outer atmosphere — and accelerating the supersonic solar wind.

Rager said she hopes to complete her doctoral work in 2019. After graduation, she hopes to continue working with the MMS team, which has both national and international colleagues in many different research institutions.

“I am excited for future missions based on similar instrumentation, which if funded, could also take advantage of this new technique,” she said.

Credits: NASA’s Goddard Space Flight Center/Joy Ng