© AGU/IBEX TeamThe IBEX results demonstrating concentrations of energetic neutral atoms. The red areas show the highest concentrations towards the Sun.
The team, from the Southwest Research Institute (SwRI) and Lockheed Martin Space Systems Company Advanced Technology Centre (ATC), used the Interstellar Boundary Explorer (IBEX) to produce a picture of the interaction between the solar wind and the Earth's outer atmosphere in March and April 2009.
The solar wind is a stream of sub-atomic particles produced by the Sun travelling out though the Solar System at over a million kilometres per hour. It interacts with the interstellar medium - particles of dust and gas that are distributed between the stars - to produce Energetic Neutral Atoms (ENAs). It is these ENAs that the IBEX satellite was designed and launched to study in October 2008.
Some of the protons and electrons in the solar wind are slowed by the Earth's atmosphere 55,000 kilometres from the surface of the Earth, creating the same ENAs from particles in the outer atmosphere. Whilst IBEX is not specifically designed to study these interactions, from its position in orbit is can observe the Earth's magnetosphere, the region where the solar wind interacts with the Earth's magnetic field. The sensors on the satellite are perfectly designed to pick up the tiny amounts (eight atoms per cubic centimetre) of ENAs created in the magnetosphere, and it is these measurements that have created so much interest.
David McComas, the IBEX principal investigator points out "these are fantastic first images of the important region where the solar wind piles up as it deflects around the Earth's magnetic field," adding that "it is particularly satisfying that we were able to use a spacecraft built for a different purpose to unwrap a mystery that has long eluded us." The IBEX measurements have been able to give a clear picture of how the concentrations of the ENAs are distributed around the Earth's magnetosphere, with the highest number found pointing towards the Sun.
The study of these interactions is important for the preservation of the Earth's atmosphere. "Without the Earth's magnetosphere, which extends outward into space, the highly energetic charged particles carried by the solar wind could strip away some of Earth's atmosphere," says Lockheed Martin's Stephen Fuselier. "The Earth's magnetosphere blocks the solar wind from penetrating close to the planet."
For a better graphic demonstration of the changes. I know NOAA has their dial display: [Link][Link]