Licentiatseminarium - Two-spacecraft studies of the plasma environment of Mars

  • Datum:
  • Plats: Ångströmlaboratoriet 80109/Zoom
  • Föreläsare: Doktorand Katerina Stergiopoulou
  • Arrangör: Institutionen för fysik och astronomi / Institutet för rymdfysik
  • Kontaktperson: Niklas Edberg
  • Licentiatseminarium

Katerina Stergiopoulou försvarar sin avhandling ”Two-spacecraft studies of the plasma environment of Mars”. Disputationen ges på engelska. Notera att på grund av begränsat antal åhörare på plats kommer seminariet att kunna följas på
Zoom: https://uu-se.zoom.us/j/63442869036
Meeting ID: 634 4286 9036, Passcode: 100938

Opponent: Associate Professor David Brain, University of Colorado
Handledare: David Andrews, Institutet för rymdfysik (IRF)

 

Abstract

The near-space environment of Mars has been probed over the last few decades by numerous missions that provided us with crucial information concerning the characterization of the Martian system. This work is a compilation of a theoretical part consisting of the fundamental features of the Martian atmosphere and ionosphere, the crustal magnetic fields and the solar wind - Mars interaction, and two studies on the Martian near-space environment. We use data from ESA’s Mars Express (MEX) and NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) missions in order to investigate the nightside ionosphere as well as the response of the Martian induced magnetosphere
to various changing parameters. First we conducted a two-spacecraft study, using simultaneous data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board MEX and the Solar Wind Ion Analyzer (SWIA) instrument and the magnetometer (MAG) on board MAVEN. We looked at five MEX orbits from September 2016 during which, unique MARSIS operations were   with the radar sampling in the induced magnetotail at altitudes up to 3,500 km. MAVEN happened to be located in the solar wind for two out of the five MEX orbits, and plasma was detected in the magnetotail both for steady and perturbed solar wind. We found a consistent
presence of plasma structures in the terminator region and transient plasma blobs deep in the nightside. Next, using again simultaneous measurements from MEX and MAVEN, we studied the response of the global Martian induced magnetosphere to various factors. Even though MEX does not carry a magnetometer, the magnetic field magnitude can be inferred by the cyclotron echoes often appearing in MARSIS’ ionograms. Having these measurements of the magnetic field magnitude from MEX sampling in the induced magnetosphere, we then test the ratio of the magnetic field MARSIS measures over interplanetary magnetic field (IMF) measurements from MAVEN, against several parameters, such as the solar wind dynamic pressure, solar wind density and speed and
Mach number. This second study is an ongoing project and the next step is to investigate the seasonal effects and the extreme ultraviolet (EUV) irradiance and crustal fields influence.