Joint Astrophysics/Space Physics Seminar

October 31, 2017 - 12:30pm
309 VAN

"Measuring Electrons in Space: Techniques and Pitfalls" by, Mr. Gian Anderone., Department of Physics & Astronomy, University of Iowa

Abstract:  Particle measurements in space environments give information on both the plasma in that environment and how the plasma interacts with its environment. Specifically, high resolution electron measurements can be used to measure planetary loss cones and the solar wind strahl. However, these measurements can be distorted relatively easily by spacecraft charging, secondary electron creation, and various other perils in space. In this talk, I will first give an overview of an Electrostatic Analyzer in development which takes both high-resolution and coarse electron measurements. As fine as these measurements look theoretically, I will show several locations on the design which could potentially produce secondary electrons. I will also present examples from MAVEN's electron instrument SWEA to demonstrate how naively using this data without any corrections for secondary electrons and spacecraft potential can lead to bad results and conclusions.

“Correcting Parker Solar Probe Electron Measurements for the Effects of Spacecraft Electrostatic and Magnetic Fields” by Mr. Daniel McGinnis, Department of Physics & Astronomy, University of Iowa

Abstract:  The Parker Solar Probe is likely to charge to a large range of spacecraft potentials, from up to a few tens of volts to perhaps even negative potentials near closest approach. This spacecraft potential will combine with the permanent magnetic fields created by spacecraft components to significantly perturb thermal electron trajectories. I will show how models of the spacecraft E and B fields can be used with particle tracing simulations to predict how measurements of the electron distribution function are likely to be affected. Further, the development of a measurement correction factor derived from this information will be discussed.