X‐ray emission from the terrestrial magnetosheath including the cusps

Abstract

X rays are produced throughout the terrestrial magnetosheath as a consequence of charge transfer collisions between heavy solar wind ions and exospheric neutrals. The solar wind ions resulting from these collisions are left in highly excited states and emit extreme ultraviolet or soft X‐ray photons. We previously simulated X‐ray images of the magnetosheath as seen from an observation point outside the geocorona for average solar wind conditions. The locations of the bow shock and magnetopause were evident in these images, but the cusps were not taken into account. For the current paper we used dynamic three‐dimensional MHD simulations of the solar wind, magnetosheath, and magnetosphere for the 31 March 2001 geomagnetic storm. A sky map was generated of the expected X‐ray emissions as seen by a hypothetical X‐ray detector on the IMAGE spacecraft. Modeled images as seen from an observation point well outside the geocorona were also created. The cusps can clearly be detected in both types of simulated images. Images of the magnetosheath in energy neutral atoms (ENA) also show the cusps. X‐ray imaging of the magnetosheath, revealing the structure of the magnetopause and the bow shock, if carried out, could potentially make a valuable contribution to our understanding of the solar wind interaction with the magnetosheath.