Seminar: Wave-Driven Processes in Electric Propulsion Devices

Abstract

Electric propulsion (EP) is a key enabling technology for the future commercialization and exploration of space.    Its high-specific impulse and efficiency translate to higher payload mass fractions when compared to traditional forms of in-space propulsion, and in some cases, EP devices can offer faster transit times for deep space missions.   Despite the many advantages offered by EP, however, there are a number of fundamental processes underlying the operation of these devices---particularly the role of plasma waves---that are not well understood.  This talk primarily is concerned with examining how these types of instabilities govern the behavior of one of the most successful EP systems flown to date, the Hall thruster.  In particular, the onset of acoustic-like turbulence is investigated experimentally and analytically, and it is shown to have a dominant impact on both the lifetime and the flow dynamics in these devices.   This talk also illustrates how wave-driven processes may be harnessed has a mechanism to drive the next-generation of EP concepts.  Devices that utilize wave-based acceleration can offer significant improvements in terms of lifetime and efficiency over EP systems currently flown.  The theoretical basis for one type of wave -based thruster is presented along with the results of an on-going experimental campaign to characterize its performance.  The presentation concludes with a discussion of the type and extent of future investigations that will be necessary to meet the growing demand for fundamental research on electric propulsion.

About the Speaker

Dr. Benjamin Jorns received his doctorate from Princeton University in mechanical and aerospace engineering in 2012.   His thesis work focused on investigating plasma heating by means of nonlinear plasma wave interactions.   In 2013, he joined the Electric Propulsion Group at the NASA Jet Propulsion Laboratory (JPL), California Institute of Technology in Pasadena, CA.   His research interests at JPL include hollow cathode erosion, plasma instabilities in Hall thrusters, advanced plasma diagnostics for electric propulsion, and analytical modeling of electron transport in EP-related devices.   Dr. Jorns also holds a lecturer position in aerospace engineering at the University of California, Los Angeles.