MAVEN Observations of Metallic Fe+ Distributions in the Martian Ionosphere

Metallic ions deposited in planetary atmospheres via meteoroid ablation are an invaluable tool for understanding electric fields, atmospheric winds, and minor ion transport. At Mars, metallic ion distributions are poorly understood. We analyze MAVEN/NGIMS Fe+ distributions in the Martian ionosphere over the period of 2015–2020 at altitudes ∼120–200 km. The Fe+ vertical structure observed during individual low‐altitude MAVEN Deep Dip campaigns is highly variable likely due to variations in the ion magnetization altitude and corresponding ion transport conditions. Deep Dip campaigns on or near the martian nightside show evidence for in situ production of Fe+ ions via electron precipitation. On average, Fe+ ions are globally distributed in the martian ionosphere at altitudes >120 km with only slight decreases on the martian nightside and in the southern hemisphere. We find a similar, albeit less intense, decrease in the Fe+ densities in the northern hemisphere near perihelion as has been reported for Mg+.