NASA - National Aeronautics and Space Administration

Schematic View of Mercury’s Magnetosphere and Heavy Plasma Ion Flux

Mercury’s planetary magnetic field largely shields the surface from the supersonic solar wind emanating continuously from the Sun. MESSENGER has been in a near-polar, highly eccentric orbit (dashed red line) since 18 March 2011. Maxima in heavy ion fluxes observed from orbit are indicated in light blue.

Credit: Courtesy of Science/AAAS