The Significance of the Ambipolar Electric Field in the Martian Ionosphere
Abstract
Ambipolar electric field provides an important mechanism for the loss of planetary ions. This mechanism is particularly effective at Mars, where the atmosphere and the ionosphere have large gradients with respect to both solar zenith angle and altitude and where the planet is not protected by a global magnetic field. Using the four years of data obtained between 2015 and 2018 by the Langmuir Probe and Waves (LPW) instrument aboard the MAVEN spacecraft, we analyze the efficiency of this force. The goal of this study is to identify the regions where the ambipolar field is strongest and could lead to significant ion upflow.
By integrating the upward ambipolar electric field over an altitude range starting form about 200-250 km—where the ion-neutral collision frequency falls below the ion gyrofrequency—to the altitude of 600 km—i.e., the top of Martian ionosphere—we estimate that the net potential in the radial direction is below 1 V on the dayside while it approaches to small values on the nightside. Here we discuss the variations of the ambipolar field as a function of the local time.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.P51H2976A
- Keywords:
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- 2437 Ionospheric dynamics;
- IONOSPHEREDE: 2459 Planetary ionospheres;
- IONOSPHEREDE: 5435 Ionospheres;
- PLANETARY SCIENCES: SOLID SURFACE PLANETSDE: 5443 Magnetospheres;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS