Scientists have discovered an entirely new magnetic phenomenon in the outer reaches of Earth's magnetic field with the help of four NASA spacecraft, according to a new study published in the journal Nature.
The spacecraft form part of the Magnetospheric Multiscale mission, which is designed to study so-called magnetic reconnection—a physical process that occurs commonly throughout the universe in magnetic fields.
"An explosion of TNT is a release of chemical energy. An atomic bomb is a release of nuclear energy. Magnetic reconnection is a 'magnetic explosion'—that is, a sudden release of magnetic energy," Michael Shay from the University of Delaware, an author of the study, told Newsweek. "Magnetic reconnection causes these explosions in many regions in space. Solar flares on the sun, for example, are caused by magnetic reconnection. Large aurorae on the Earth are due to energetic particles created by magnetic reconnection."
Jonathan Eastwood, a physicist from Imperial College London and another author of the study, added, "Although we think of space as empty, it's not! It's filled with particles and fields, so called 'space plasmas.' When energy is released by reconnection, it creates hot jets of plasma." Plasma a super-hot form of gas that is one of the four fundamental states of matter.
Now, for the first time, the process of magnetic reconnection has been observed in a turbulent region of the Earth's outer atmosphere known as the magnetosheath—which acts as the first line of defense against the barrage of hot, charged particles produced by the sun, known as the solar wind.
The latest findings could provide insights into how these magnetic phenomena affect Earth's atmosphere, as well as astronauts in space, satellites, electrical power industries, radio communications and GPS systems.
The new type of magnetic reconnection, known as electron magnetic reconnection, works differently from the type that commonly occurs in the lower, less turbulent regions of the Earth's magnetosphere—the magnetic fields that surround our planet.
Most think of turbulence as the air currents which can cause a plane ride to be uncomfortably bumpy. However, turbulence also occurs elsewhere in the universe.
"Turbulence is characterized by seemingly random flows of a gas, liquid or plasma," Shay said. "We all have seen it or experienced it: the stream of smoke from a cigarette breaks up; the creamer we pour in our coffee makes beautiful patterns before it completely mixes; a plane ride gets bumpy when it travels through turbulence in our atmosphere."
He continued, "Many regions in space have turbulent plasma. The outer layers of the sun are turbulent. The solar wind blasted off by the sun is turbulent. This solar wind smashes up against the Earth's magnetic field, creating a turbulent sheath of plasma around near-Earth space."
The turbulence in this magnetosheath contains a lot of magnetic energy, which is a result of it being bombarded by particles from the sun's corona that travel at around 1 million miles per hour. This region is where the scientists made their discovery.
"We found reconnection happening on very small scales, smaller than ever seen before," Eastwood said. "It is important because ultimately the turbulent energy must be dissipated as heat. For a long time, we have debated how this happens, and there are lots of theories. This result shows that reconnection could play that role."
By better understanding the processes of turbulence and reconnection, we'll be able to know more about how similar processes work in a variety of fields. This could have a number of implications.
"The ultimate goal of our research is to understand the physics well enough to create predictive space weather models," Shay said. "As an analogy, for regular weather, atmospheric models are used extensively to guide NOAA weather predictions. With better models, we can predict space weather hazards several days before they occur, allowing mitigation activities: one, satellite operators can put their multimillion-dollar satellites in 'safe' mode, or two, military planners can expect possible communication disruptions."
He continued, "In addition, NASA is pushing to return man to the moon and eventually send a manned mission to Mars. In these missions, our spacecraft have to leave the protective bubble of the Earth's magnetic field, or magnetosphere. If we can't predict space weather events, we could be putting astronauts in harm's way.
"For example, reconnection in turbulence may be important for creating these high-energy particles, which can hurt astronauts. We have to understand if it is and what implications it has for space weather," Shay said.
