Physicists at the University of Alberta, Canada, say they have discovered a surprising imbalance in how the Earth responds to space weather driven by the sun. Energy generated as the electrically charged particles in solar wind hit Earth result in more electromagnetic energy heading toward the magnetic north pole than to the magnetic south pole.
Until now, it was assumed the same amount of electromagnetic energy in space would reach both hemispheres of the planet. However, using information from the European Space Agency’s (ESA) Swarm satellite constellation, the team discovered that electromagnetic energy transported by space weather clearly prefers the north. A key component of the research involved data from an electric field instrument developed in Canada by the University of Calgary. The research discovery resulted from a partnership between the two Alberta universities and ESA.
“We are fortunate that we have ESA’s three Swarm satellites in orbit, delivering key information that is not only vital for our scientific research, but can also lead to some very practical solutions for our daily lives,” said U of A co-author Ian Mann, professor in the Department of Physics.
“Because the south magnetic pole is farther away from Earth’s spin axis than the north magnetic pole, an asymmetry is imposed on how much energy makes its way down toward Earth in the north and south,” explained Ivan Pakhotin, lead author and post-doctoral fellow in the Department of Physics.
The new findings suggest that in addition to shielding Earth from incoming solar radiation, the magnetic field also actively controls how the energy is distributed and channeled into the upper atmosphere.
“We are not yet sure what the effects of this asymmetry might be, but it could also indicate a possible asymmetry in space weather and perhaps also between the aurora australis in the south and the aurora borealis in the north,” added Pakhotin. “Our findings also suggest that the dynamics of upper atmospheric chemistry may vary between the hemispheres, especially during times of strong geomagnetic activity.”
The study, “Northern preference for terrestrial electromagnetic energy input from space weather,” was published in Nature Communications.