Scientists discover a long-sought global electric field on Earth

Amazing stuff!

"Using observations from a NASA suborbital rocket, an international team of scientists, for the first time, has successfully measured a planet-wide electric field thought to be as fundamental to Earth as its gravity and magnetic fields.

Known as the ambipolar electric field, scientists first hypothesized over 60 years ago that it drove how our planet's atmosphere can escape above Earth's North and South Poles. Measurements from the rocket, NASA's Endurance mission, have confirmed the existence of the ambipolar field and quantified its strength, revealing its role in driving atmospheric escape and shaping our ionosphere—a layer of the upper atmosphere—more broadly. ...
Svalbard, a Norwegian archipelago just a few hundred miles from the North Pole and home to the northernmost rocket range in the world. ..."

"Key Points

• A rocket team reports the first successful detection of Earth’s ambipolar electric field: a weak, planet-wide electric field as fundamental as Earth’s gravity and magnetic fields.
• First hypothesized more than 60 years ago, the ambipolar electric field is a key driver of the “polar wind,” a steady outflow of charged particles into space that occurs above Earth’s poles.
• This electric field lifts charged particles in our upper atmosphere to greater heights than they would otherwise reach and may have shaped our planet’s evolution in ways yet to be explored.

..."

From the abstract:

"Cold plasma of ionospheric origin has recently been found to be a much larger contributor to the magnetosphere of Earth than expected. Numerous competing mechanisms have been postulated to drive ion escape to space, including heating and acceleration by wave–particle interactions and a global electrostatic field between the ionosphere and space (called the ambipolar or polarization field). Observations of heated O+ ions in the magnetosphere are consistent with resonant wave–particle interactions. By contrast, observations of cold supersonic H+ flowing out of the polar ionosphere (called the polar wind) suggest the presence of an electrostatic field. Here we report the existence of a +0.55 ± 0.09 V electric potential drop between 250 km and 768 km from a planetary electrostatic field (E∥⊕ = 1.09 ± 0.17 μV m−1) generated exclusively by the outward pressure of ionospheric electrons. We experimentally demonstrate that the ambipolar field of Earth controls the structure of the polar ionosphere, boosting the scale height by 271%. We infer that this increases the supply of cold O+ ions to the magnetosphere by more than 3,800%, in which other mechanisms such as wave–particle interactions can heat and further accelerate them to escape velocity. The electrostatic field of Earth is strong enough by itself to drive the polar wind and is probably the origin of the cold H+ ion population that dominates much of the magnetosphere."

Scientists discover a long-sought global electric field on Earth

NASA Discovers a Long-Sought Global Electric Field on Earth (original news release)

Earth’s ambipolar electrostatic field and its role in ion escape to space (no public access, but article above contains link to PDF)