SCHOOL OF EARTH AND ATMOSPHERIC SCIENCES

EAS Ph.D. Defense

Joshua Mendez

June 20, 2017

2:00 PM

Earth and Atmospheric Sciences

Ford Environmental Science & Technology (ES&T)311 Ferst Drive, ES&T Atlanta, GA 30332-0340

Web: eas.gatech.edu

ES&T Room L1114

Title: Granular electrification on Earth and other worlds

Committee members: Dr. Dufek, Dr. Newman, Dr. Peng,Dr. Steffes(ECE), Dr. Ferrier

Abstract: When mobilized granular substances become electrostatically charged as constituent grains undergo collisions, as particles fracture, or through induction processes associated with external electric fields. In man made settings, such charging may lead to problems during the transport of agricultural or pharmaceutical substances. In natural contexts perhaps the most dramatic demonstration of electrostatic processes in granular flows are the energetic displays of lightning that often accompany large volcanic eruptions. In this work, we explore the microphysics that leads to charging in a broad range of environments, both on Earth and other worlds. We find that granular electrostatic processes are sensitive to a wide range of parameters, including particle chemistry, environmental conditions, and hydrodynamics. The first section of this work deals with charging in volcanic plumes, while the second addresses granular electrification on Titan and exoplanet GJ1214b.