Advances in Fluxgate Magnetometry for Space Physics

  • Author / Creator
    Miles, David M
  • Fluxgate magnetometers are an essential tool for solar-terrestrial research and monitoring or forecasting space weather. They provide high precision measurements of the Earth’s magnetic fields and can be used to infer the currents that transport energy and momentum through the magnetosphere and ionosphere. This thesis is a compilation of four journal articles describing instrumentation design advances and applications of fluxgate magnetometers for space physics. It presents the design and performance of the Magnetic Field Experiment (MGF) fluxgate magnetometer component of the Enhanced Plasma Outflow Probe (e-POP) payload on the multi-purpose Canadian Space Agency CASSIOPE small satellite mission. Since its launch on September 29, 2014, The MGF has successfully produced high-cadence low-noise measurements of the Earth’s magnetic field that have been used for a variety of research topics including the study of dynamic small-scale auroral currents. Following the success of the MGF, the design was updated and miniaturised to form the Digital Fluxgate Magnetometer (DFGM) payload, which will launch in early 2017 on the Experimental Albertan #1 CubeSat (Ex-Alta 1). The flight of this small, low-mass, low-power, low-magnetic noise, and boom-mounted fluxgate magnetometer will demonstrate the potential for high-fidelity magnetic field measurements on future multi-spacecraft CubeSat constellation missions. Fluxgate magnetometers have long been known to be sensitive to variations in sensor temperature and to therefore require appropriate thermal calibration. A novel, low-cost thermal calibration procedure was used to compare the thermal stability of six experimental fluxgate sensors constructed from a variety of materials. Polyetheretherketone (PEEK) with 30% glass content was found to be a promising replacement for traditional expensive and difficult to machine ceramic for future low-cost, low-mass sensors. This dataset also shows the limitations of the traditional model for how fluxgate sensor geometry and materials control its thermal gain. Finally, measurements from e-POP and the adjacent European Space Agency Swarm A and C spacecraft were used to study the dynamics and structuring of discrete arc aurora. A case study supported by high-cadence auroral imaging shows 1-10 km structuring of the arcs, which move and evolve on second timescales and confound the traditional field-aligned current algorithms. Non-stationary electrodynamics involving reflected and interfering Alfvén waves were observed co-incident with, and at the same scale as, dynamic auroral structures. Spectral analysis of in-situ electric and magnetic measurements shows evidence of a potential role for the Ionospheric Alfvén Resonator in discrete arc dynamics. Improved instruments and techniques are needed to fully understand the highly dynamic and localised processes that couple mass and energy through near-Earth space and thereby control space weather. The presented research demonstrates that multi-spacecraft constellation missions featuring modern, low-resource fluxgate magnetometers to provide high-fidelity magnetic field measurements can play a crucial role in future space physics research.

  • Subjects / Keywords
  • Graduation date
    Spring 2017
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.
  • Language
  • Institution
    University of Alberta
  • Degree level
  • Department
  • Specialization
    • Geophysics
  • Supervisor / co-supervisor and their department(s)
  • Examining committee members and their departments
    • Moldwin, Mark (Climate and Space Sciences and Engineering)
    • Fedosejevs, Robert (Electrical and Computer Engineering)
    • Mann, Ian (Physics)
    • Unsworth, Martyn (Physics)
    • Sydora, Richard (Physics)