NASA scientists have discovered a third global energy field surrounding Earth. The ambipolar electric field drives charged particles into space above the poles.
It is known that there are two primary global fields around Earth: the gravitational field created by the planet's mass and the electromagnetic field produced by the metals in the planet's core. The hypothesis of a third field had been proposed for decades, but new NASA research has finally confirmed it through measurements.
“This electric field is bidirectional or ambipolar, as it acts in both directions. Ions pull electrons downward as they fall under the influence of gravity. At the same time, electrons lift ions to greater heights when they attempt to escape into space,” NASA stated.
Since the 1960s, spacecraft flying over Earth's poles have detected far more particles escaping from the atmosphere into space than expected. This “polar wind” oddly consisted of particles moving at supersonic speeds, even though they remained cold, contrary to expectations. Scientists hypothesized that this could result from a phenomenon they termed the ambipolar electric field.
According to the hypothesis, this field should originate at an altitude of about 250 km above the poles. At this altitude in the atmosphere, electrons are easily ejected from hydrogen and oxygen atoms, leaving positively charged ions. These ions are significantly heavier than electrons, so if gravity were the only force acting on them, over time they would fall downward while electrons would escape into space.
However, since ions and electrons have opposite charges, they continue to attract each other. This results in an expansion of the “scale height” of the atmosphere above the poles, effectively making it denser at higher altitudes.
This ambipolar electric field would be extremely weak and could only be detected from hundreds of kilometers away, which is why no instrument was sensitive enough to capture it previously. The goal of the NASA Endurance mission was to test this hypothesis once and for all, and it achieved results.
The culmination of the mission was the launch on May 11, 2022, from the northernmost rocket launch site in the world, located on the Svalbard archipelago north of Norway. There, Endurance embarked on a 19-minute mission to study this field.
Onboard instruments measured changes in electric potential from the altitude where the field should begin to the maximum altitude it reached—768 km. They indeed detected a change of 0.55 V.
“A fraction of a volt is almost nothing, about the same as a watch battery. But it’s exactly what is needed to explain the polar wind,” says Glynn Collinson, the lead researcher of the Endurance mission.
It may not sound very powerful, but for hydrogen ions, the most common type in the polar wind, this electric field generated a force over ten times greater than gravity, helping to propel them into space at supersonic speeds. Oxygen ions also received a significant boost. The experiment also established an increase in the height of the ionosphere by 271%.
Now that this electric field has finally been detected, scientists can begin to investigate how it has influenced atmospheric changes throughout Earth's history. The study has been published in the journal Nature. A popular description of the research is presented in NASA's publication linked below, as well as in the video.
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