Advanced Instrumentation and Flux Mapping Techniques for the Study of the Space Environment.

Abstract

The study of particle populations such as the solar wind, pickup ions, and energetic particles, provides clues to the physical processes that govern the space environment. Some of these particle populations are not well understood due to their low densities and the low-sensitivity of instruments that are not specifically designed to search for them. With a new technique for mapping the solar magnetic field on which energetic particles travel, as well as improved instrumentation with the sensitivity necessary to measure low-density particle populations, the research outlined here will provide a new, powerful set of tools for studying the space environment. The Diffusive Equilibrium Mapping technique takes any footpoint of open magnetic flux on the solar surface and calculates where it reaches in the heliosphere, assuming pressure equilibrium. This method can model magnetic flux configurations that include open flux distributed outside of coronal holes, which may contribute to the source of streamer solar wind. Certain limitations on plasma mass spectrometers are investigated and overcome in the IonSpec design, which is capable of measuring an energy-per-charge passband of (E/q)max = 3(E/q)min in a single voltage step. IonSpec has a larger integration time, geometric duty cycle, and energy-geometrical factor than similar instruments and is capable of measuring the elemental abundances and ionic charge composition of all major solar wind and pickup ion species. In addition, a novel modification to cylindrically symmetric linear-electric-field time-of-flight analyzers allows for the focusing of secondary electrons emitted by the impact of isochronous ions. By identifying secondary electron peaks using their impact position, a single anode can be used to record both straight-through and isochronous flight times without a loss in the high-resolution isochronous measurement from a low signal-to-noise ratio. The new mapping technique and novel instrument designs will enable studies of the space environment that were previously not possible.