Description
- Abstract:
- Upon hypervelocity impact, projectile and target materials are frequently shocked to pressures and temperatures sufficient to induce complete vaporization. Vaporization associated with impacting comets and asteroids controls much of the geophysical and compositional evolution of planetary systems. A sampling of planetary science problems traceable to impact vaporization phenomena include: generation and deposition of nanophase iron within lunar soil rims, the Moon-forming impact, the accretionary histories of the icy satellites, erosion of the early Martian atmosphere, target degassing consequences for the terrestrial biosphere from catastrophic impacts, and impact delivery of organics or volatiles to planetary surfaces. Numerical methods to constrain impact vaporization have made enormous strides over the past two decades, perhaps catalyzed (in part) by the fortuitous 1994 impact of Jupiter by Comet Shoemaker-Levy 9. Such planetary-scale impact "experiments" provide rare glimpses of the remarkable, high-energy vapor plumes released during impact events. Accurate modeling of impact-generated vapor, however, relies heavily upon the availability of robust equations of state and constitutive relations for the target and projectile materials of interest. Continued work to constrain the behavior of geologic materials at high temperatures and pressures, coupled with accelerating parallel computing capabilities, has opened up a new frontier of planetary-scale impact vaporization problems, as evidenced by recent, vigorous work on the Moon-forming impact. While numerical methods are powerful and necessary for considering planetary-magnitude events, experimental strategies to characterize impact vaporization remain critical for testing the roles of various impactor and target material models. Furthermore, modeling of oblique impacts remains relatively difficult and computationally expensive; certain experimentally resolved trends, including enhanced vaporization at lower incidence angles, are not yet captured numerically. Nature favors oblique impacts: the impact angle probability distribution peaks at 45 degrees. Hence, a comprehensive approach to impact vaporization problems will consider impacts beyond the frequently modeled 90 degree case. Here we employ a hybrid approach: both experimental and numerical methods provide complementary insights to impact vaporization phenomena. A wide range of planetary science problems are considered, but all are intimately tied to the way in which planetary surfaces and impactors vaporize.
- Notes:
- Thesis (Ph.D. -- Brown University (2014)
Access Conditions
- Rights
- In Copyright
- Restrictions on Use
- Collection is open for research.
Citation
Syal, Megan B.,
"Impact Vaporization: Experimental and Numerical Insights"
(2014).
Earth, Environmental and Planetary Sciences Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z08050Z0
Relations
Collection:
-
Earth, Environmental and Planetary Sciences Theses and Dissertations
Theses and Dissertations for the Earth, Environmental and Planetary Sciences department....