Formation of Ammonia through Meteoritic Atmospheric Entry: Implications for the Prebiotic Chemical Process on Earth*

Utilizing the DIII-D tokamak, the Divertor Material Evaluation System (DiMES), and chemical analysis, a first order identification of ammonium (cation of ammonia when placed in solution) was observed in the divertor plasma of the tokamak to reproduce atmospheric entry conditions of meteoroids entering Earth. Ammonia is a compound that yields many benefits in the prebiotic chemical processes as it is present in the Urea, Ammonium Formate, and Water system that helps promote the dissolution of phosphate and the phosphorylation of nucleosides. Employing numerical modeling along with empirical analysis, we investigate if a meteoroid entering Earth could produce ammonia through plasma-material interactions during the atmospheric entry process. Numerical modeling of meteoroid ablation shows that meteoroids entering the atmosphere can indeed produce enough energy to overcome the activation energy needed to promote synthesis of ammonia. To test these predictions, we designed a DIII-D experiment where carbon and silica powders were injected in the edge plasma during simultaneous puffing of nitrogen-hydrogen gas mixture. Here we present the predictions from the ablation simulations, scaling to DIII-D plasma conditions, experimental design, and initial experimental results. Mass spectrometry analysis of the plasma exhaust and a post-mortem chemical analysis of collector probes (aluminum pistons within the DiMES head) suggest the production of ammonia during the experiment.

Work supported by US DOE under DE-SC0022554, DE-SC0021338, DE-SC0023375, DE-SC0023367, and DE-FC02-04ER54698.