A new analysis of the measurements of five different satellites has revealed the existence of the warm plasma cloak, a new region of the magnetosphere, which is the invisible shield of magnetic fields and electrically charged particles that surround and protect Earth from the onslaught of the solar wind.

The study was conducted by a team of scientists headed by researchers at Vanderbilt University, according to a press release by the university on Friday.

Although invisible, the magnetosphere has an impact on Earth. For example, solar storms agitate the magnetosphere in ways that can induce power surges in the electrical grid that trigger blackouts, interfere with radio transmissions and mess up GPS signals.

The other regions of the magnetosphere have been known for some time. The research team pieced together a "natural cycle of energization" that accelerates the low-energy ions that originate from Earth's atmosphere up to the higher energy levels characteristic of the different regions in the magnetosphere. This brought the existence of the new region into focus.

The warm plasma cloak is a tenuous region that starts on the night side of the planet and wraps around the dayside but then gradually fades away on the afternoon side.

As a result, it only reaches about three-quarters of the way around the planet. It is fed by low-energy charged particles that are lifted into space over Earth's poles, carried behind the Earth in its magnetic tail but then jerked around 180 degrees by a kink in the magnetic fields that boosts the particles back toward Earth in a region called the plasma sheet.