Reconnection - Blog Posts

Our Spacecraft Have Discovered a New Magnetic Process in Space

Just as gravity is one key to how things move on Earth, a process called magnetic reconnection is key to how electrically-charged particles speed through space. Now, our Magnetospheric Multiscale mission, or MMS, has discovered magnetic reconnection – a process by which magnetic field lines explosively reconfigure – occurring in a new and surprising way near Earth.

Invisible to the eye, a vast network of magnetic energy and particles surround our planet — a dynamic system that influences our satellites and technology. The more we understand the way those particles move, the more we can protect our spacecraft and astronauts both near Earth and as we explore deeper into the solar system.

Earth’s magnetic field creates a protective bubble that shields us from highly energetic particles that stream in both from the Sun and interstellar space. As this solar wind bathes our planet, Earth’s magnetic field lines get stretched. Like elastic bands, they eventually release energy by snapping and flinging particles in their path to supersonic speeds.

That burst of energy is generated by magnetic reconnection. It’s pervasive throughout the universe — it happens on the Sun, in the space near Earth and even near black holes.

Scientists have observed this phenomenon many times in Earth’s vast magnetic environment, the magnetosphere. Now, a new study of data from our MMS mission caught the process occurring in a new and unexpected region of near-Earth space. For the first time, magnetic reconnection was seen in the magnetosheath — the boundary between our magnetosphere and the solar wind that flows throughout the solar system and one of the most turbulent regions in near-Earth space.

The four identical MMS spacecraft — flying through this region in a tight pyramid formation — saw the event in 3D. The arrows in the data visualization below show the hundreds of observations MMS took to measure the changes in particle motion and the magnetic field.

The data show that this event is unlike the magnetic reconnection we’ve observed before. If we think of these magnetic field lines as elastic bands, the ones in this region are much smaller and stretchier than elsewhere in near-Earth space — meaning that this process accelerates particles 40 times faster than typical magnetic reconnection near Earth. In short, MMS spotted a completely new magnetic process that is much faster than what we’ve seen before.

What’s more, this observation holds clues to what’s happening at smaller spatial scales, where turbulence takes over the process of mixing and accelerating particles. Turbulence in space moves in random ways and creates vortices, much like when you mix milk into coffee. The process by which turbulence energizes particles in space is still a big area of research, and linking this new discovery to turbulence research may give insights into how magnetic energy powers particle jets in space.

Keep up with the latest discoveries from the MMS mission: @NASASun on Twitter and Facebook.com/NASASunScience.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com. 

Exploring the Invisible: Magnetic Reconnection

People always say that space is a vacuum. That’s true – space is about a thousand times emptier than even the best laboratory vacuums on Earth. Even so, space contains lots of stuff we can’t see. We study this invisible space stuff because we need to understand it to safely send technology and astronauts into space.

The stuff that fills space is mostly plasma, which is gas where particles have separated into positive ions and negative electrons, creating a sea of electrically-charged particles. This plasma also contains something else – magnetic fields.

The particles in space can reach very high speeds, creating radiation. One of the main engines that drives that acceleration to high speeds is called magnetic reconnection. But what is magnetic reconnection?

Magnetic reconnection happens when two oppositely-aligned magnetic fields pinch together and explosively realign. As the lines snap into their new configuration – as in the animation below – the sudden change sends electrons and ions flying at incredible speeds.

Magnetic reconnection releases energy. We can't see the energy itself, but we can see the results: It can set off solar explosions – such as solar flares and coronal mass ejections – or disturbances near Earth that cause auroras.

In March 2015, we launched the four Magnetospheric Multiscale, or MMS, spacecraft on a mission to study magnetic reconnection. Magnetic reconnection only happens in a vacuum with ionized gas. These conditions are vanishingly rare on Earth, so we went to space to study this explosive process.

Because MMS has four separate – but essentially identical – spacecraft, it can watch magnetic reconnection in three dimensions.

The below animation shows what MMS sees – the magnetic fields are magenta, positive ions are purple, and electrons are yellow. The arrows show which the direction the fields and particles are moving.

Like how a research plane flies through a hurricane, MMS flew directly through a magnetic reconnection event in October 2015.

In the data visualization below, you can see the magnetic reconnection happening as the yellow arrows (which represent electrons) explode in all directions. You’ll notice that the magnetic field (represented by magenta arrows) changes direction after the magnetic reconnection, showing that the magnetic field has reconfigured.

Magnetic reconnection transfers energy into Earth’s atmosphere – but it’s not inherently dangerous. Sometimes, the changes in Earth’s magnetic field caused by magnetic reconnection can create electric currents that put a strain on power systems. However, the energy released is more often channeled into auroras, the multicolored lights that most often appear near the North and South Poles.

As the MMS mission continues the four spacecraft can be moved closer together or farther apart, letting us measure magnetic reconnection on all different scales. Each set of observations contributes to explaining different aspects of this invisible phenomenon of magnetic reconnection. Together, the information will help scientists better map out our space environment — crucial information as we journey ever farther beyond our home planet.

Make sure to follow us on Tumblr for your regular dose of space: http://nasa.tumblr.com