NASA Mission: Interaction Between Magnetic Fields Of Earth And Sun Revealed For The First Time

The earth's magnetic field is a powerful and important protective cover from the sun's magnetic field. A new study uses information from NASA's Magnetospheric Multiscale (MMS) mission to examine the interaction between the magnetic fields of the earth and the sun. It offers a direct observation of magnetic reconnection that takes place when two opposing magnetic field lines break and later get back through reconnection.

"Imagine two trains traveling toward each other on separate tracks, but the trains are switched to the same track at the last minute," said James Drake, a professor of physics at the University of Maryland and co-author of the study. "Each track represents a magnetic field line from one of the two interacting magnetic fields while the track switch represents a reconnection event. The resulting crash sends energy out from the reconnection point like a slingshot."

While reconnection is a major driving force behind interstellar events such as solar flares and magnetic storms, this is the first time a direct observation of this phenomenon has happened.

The MSS spacecraft has been flying in a pyramid formation at the edge of the earth's magnetic field. It has captured electrons inside the pyramid at every 30 milliseconds, compared to the earlier Cluster II mission, which took measurements every three seconds.

"Just looking at the data from MMS is extraordinary," Drake said. "The level of detail allows us to see things that were previously a blur. With a time interval of three seconds, seeing reconnection with Cluster II was impossible. But the quality of the MMS data is absolutely inspiring. It's not clear that there will ever be another mission quite like this one."

The magnetic reconnection can enable scientists to get an insight into space weather and also potential patterns similar to the ones observed in the weather on Earth. Moreover, it can also help us understand related astrophysical phenomena such as magnetars. These are names of neutron stars with a powerful magnetic field.

"Understanding reconnection is relevant to a whole range of scientific questions in solar physics and astrophysics," said Marc Swisdak of the University of Maryland, who was not involved in the study.

"Reconnection in Earth's magnetic field is relatively low energy, but we can get a good sense of what is happening if we extrapolate to more energetic systems," he added. "The edge of Earth's magnetic field is an excellent test lab, as it's just about the only place where we can fly a spacecraft directly through a region where reconnection occurs."

The findings were published in the May 12, 2016, issue of the journal Science.