Solar wind- and EUV-dependent models for the shapes of the Martian plasma boundaries based on Mars Express measurements

• The long operational life (2003-present) of Mars Express (MEX) has allowed the spacecraft tomake plasma measurements in the Martian environment over a wide range of upstream conditions. Wehave analyzed ∼7000 MEX orbits, covering three orders of magnitude in solar wind dynamic pressure, withdata from the on board Analyzer of Space Plasmas and Energetic Particles (ASPERA-3) package, mappingthe locations where MEX crosses the main plasma boundaries, induced magnetosphere boundary (IMB), ionosphere boundary (IB), and bow shock (BS). A coincidence scheme was employed, where data fromthe Ion Mass Analyzer (IMA) and the Electron Spectrometer (ELS) had to agree for a positive boundaryidentification, which resulted in crossings from 1083 orbit segments that were used to create dynamictwo-parameter (solar wind density, nsw, and velocity vsw) dependent global dynamic models for the IMB, IB,and BS. The modeled response is found to be individual to each boundary. The IMB scales mainly dependenton solar wind dynamic pressure and EUV intensity. The BS location closely follows the location of the IMB atthe subsolar point, though under extremely low nsw and vsw the BS assumes a more oblique shape. The IBclosely follows the IMB on the dayside and changes its nightside morphology with different trends for nswand vsw. We also investigate the influence of extreme ultraviolet (EUV) radiation on the IMB and BS, findingthat increased EUV intensity expands both boundaries.

Subject headings

NATURVETENSKAP  -- Fysik -- Fusion, plasma och rymdfysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Fusion, Plasma and Space Physics (hsv//eng)

Publication and Content Type

ref (subject category)

art (subject category)