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Numerical Modeling of Dust Dynamics around Small Asteroids

Author: 
William Yu
Topic: 
Dust/Regolith
Delivered As: 
Oral
Abstract Text: 

While the dynamics of dust transport around an airless body has been a focused area of research in recent years, various challenging aspects still remain to be addressed for small asteroids where the dust dynamics is determined by the competing effects from gravitational force, electromagnetic force, and solar radiation pressure. This paper presents an investigation of dust transport and distribution around small asteroids utilizing numerical models and laboratory experiments. This investigation includes the following studies: 1) 3-dimensional fully kinetic Particle-in-Cell (PIC) simulations of plasma flow past an asteroid to determine the electric field around the asteroid and calculate surface charging. The PIC model utilizes an immersed-finite-element based field solver which is capable of resolving realistically shaped asteroid and calculating the surface potential self-consistently from charge deposition. 2) Gravitational field modeling for a realistically shaped asteroid. 3) Laboratory measurements of dust grain charging on asteroid surface in a simulated near asteroid plasma environment. 4) Dust transport simulations which incorporate the results of the PIC and gravitational field model and dust charging measurements. Simulation results are presented for the following 2 scenarios: a) electrostatically levitated dust grains and b) impact ejection of dust grains. We find that local electrostatic fields strongly influence the trajectory of charge dust grains near surface, while local gravity fields may determine distributions at further distances. We discuss the effects of asteroid composition, grain size and space plasma environments on dust levitation and transport. Implications of the study may advance the current understanding the asteroid environment and improve functionality of future spacecraft design for asteroid rendezvous mission.

Co-Authors: 
Mihály Horányi
SSERVI Identifier: 
NESF2016-145

About SSERVI
Recognizing that science and human exploration are mutually enabling, NASA created the Solar System Exploration Research Virtual Institute (SSERVI) to address basic and applied scientific questions fundamental to understanding the Moon, Near Earth Asteroids, the Martian moons Phobos and Deimos, and the near space environments of these target bodies. As a virtual institute, SSERVI funds investigators at a broad range of domestic institutions, bringing them together along with international partners via virtual technology to enable new scientific efforts."