Martian crustal magnetic fields: influences on the ionosphere

<p>Recent Mars Express and MAVEN observations have shown the extent to <br>which Mars's crustal fields, though weak in absolute magnitude, <br>nevertheless exert significant control over the structure of the ionosphere <br>over a range of altitudes. However, quantifying this control remains <br>challenging given the generally dynamic nature of the Mars solar wind <br>interaction, and the therefore naturally varying densities and temperatures <br>of the upper ionosphere in particular. In this study we examine MAVEN <br>Langmuir Probe and Waves data, and show for the first time a very clear <br>correspondence between the structure of the crustal fields and both the <br>measured electron temperatures and densities. Electron temperatures are <br>shown to be systematically lower in regions of strong crustal fields over a <br>wide altitude range. We speculate on the origins of this deviation.</p>