Phys.org August 28, 2024
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 wind suggest the presence of an electrostatic field. An international team of researchers (USA – NASA Goddard Space Flight Center, Catholic University of America, Embry-Riddle Aeronautical University, University of New Hampshire, University of Colorado at Boulder, UC Berkeley, Penn State University, NASA Wallops Flight Facility, UK, Norway, Sweden, Svalbard and Jan Mayen) described the existence of an electric potential drop between 250 km and 768 km from a planetary electrostatic field generated exclusively by the outward pressure of ionospheric electrons. They experimentally demonstrated that the ambipolar field of Earth controls the structure of the polar ionosphere, boosting the scale height by 271%. They inferred that this increased the supply of cold O+ ions to the magnetosphere by more than 3,800%, in which other mechanisms such as wave–particle interactions could 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 population1 that dominates much of the magnetosphere… read more. TECHNICAL ARTICLEÂ
The flight of the NASA rocketship Endurance. Credit: Nature volume 632, pages1021–1025, 28 August 2024