Dissertation
Improving electron measurements in space plasma environments through instrument design and data analysis
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Spring 2021
DOI: 10.17077/etd.005901
Abstract
Understanding electron properties in space plasma environments is crucial in understanding how various space plasmas evolve and interact with different obstacles, such as the difference between intrinsically unmagnetized (Mars) and intrinsically magnetized (Earth). However, care must be taken to both develop the instruments which take these measurements, as well as analyzing the data which is procured from said instruments. Starting with the basic design of a classic charged particle instrument (the tophat electrostatic analyzer), a new instrument capable of taking both high- (fine) and low- (coarse) resolution angular measurements of the different electron distributions was developed. This instrument is very similar in size and shape to charged particle instruments flown on current spaceflight missions, such as the Mars Atmosphere and Volatile Evolution (MAVEN) mission and the Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission. The compactness in both mechanical and electrical design make this instrument a prime candidate to fly on future missions which want to study both coarse and fine properties of a specific electron distributions. However electron instruments tend to experience a fair amount of measurement contamination in low energy measurement bins. This occurs mainly due to photoelectrons from the spacecraft and secondary electron produced both internally and externally to the instrument. Part of the current thesis will describe an algorithm developed to remove the secondary electron contamination which allowed better calculations of various electron properties, such as density and temperature. After the secondary contamination has been separated from the ambient plasma population, two years of electron data around Mars was analyzed to understand how electrons ultimately affect the Martian space environment. Finally a study of how the electron population can drive instabilities was performed to better understand how electrons can exchange energy with electromagnetic waves. This specific analysis showed that the ability to drive instabilities in the Martian magnetosheath is dependent on the upstream Alfven mach number in the solar wind.
Details
- Title: Subtitle
- Improving electron measurements in space plasma environments through instrument design and data analysis
- Creators
- Gian Andreone
- Contributors
- Jasper Halekas (Advisor)Craig Kletzing (Committee Member)David Mitchell (Committee Member)David Miles (Committee Member)Greg Howes (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Physics
- Date degree season
- Spring 2021
- DOI
- 10.17077/etd.005901
- Publisher
- University of Iowa
- Number of pages
- xii, 90 pages
- Copyright
- Copyright 2021 Gian Andreone
- Language
- English
- Description illustrations
- illustrations (chiefly color)
- Description bibliographic
- Includes bibliographical references (pages 81-90)
- Public Abstract (ETD)
Electrons in space plasma environments provide important information about the plasma itself and how it interacts with various obstacles. For instance, studying electrons is crucial in understanding how space weather can potentially affect satellite communications, like GPS signals, on Earth. Electrons can also help answer valuable question about planetary morphology, such as how Mars went from being a wet, warm planet to a cold, dry one over the course of a couple billion years. However, space physics missions are expensive and require an entire suite of robust but compact instruments. The current thesis shows how to develop the next generation of these instruments, as well as carefully analyzing the data and understanding various limitations. This manuscript then concludes with a case study looking at electrons at Mars and how they affect the overall morphology of the planet.
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984097074502771
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