Modeling impact ejecta plume evolution: A comparison to laboratory studies

• Published in: Journal of Geophysical Research Vol. 116; no. E12
• Main Author: Richardson, James E.
• Format: Journal Article
• Language: English
• Published: Washington Blackwell Publishing Ltd 01.12.2011
• Subjects: Excavation; impact cratering; impact ejecta; impact experiment; modeling; Planetology; Planets
• ISSN: 0148-0227; 2169-9097; 2156-2202; 2169-9100
• DOI: 10.1029/2011JE003844

This study demonstrates the efficacy of a recently developed, impact crater “excavation flow properties model” (EFPM) that accomplishes the following goals: (1) uses hydrodynamic streamline theory to develop the expressions that extend the classic impact ejecta scaling relationships into regions near the crater rim, where target strength and/or gravity bring crater excavation flow to a halt; (2) links this new, general ejecta position/velocity scaling relationship to the existing general crater size/volume scaling relationship, including the transition region between gravity‐ and strength‐dominated cratering; (3) provides a means for estimating impact ejecta plume mass‐density and ejecta blanket thickness, as a function of azimuth and distance from the impact site, in conditions ranging from low to high target strength; and (4) brings in our experimentally derived knowledge of impact ejection angles and the effects of oblique impact to develop a useful 2‐D and 3‐D model of both leading‐edge and trailing‐edge ejecta plume behavior. In this work, this excavation flow properties model is used to simulate the images and data produced by three laboratory impact studies which utilized modern, laser‐based, non‐intrusive means to investigate ejecta plume formation, expansion, and fallout from three different perspectives. Key Points This work demonstrates a model of laboratory‐scale impact ejecta behavior The model works for conditions of both gravity and strength dominated cratering The model includes the effects of oblique impact in phenomenological fashion