A5076180417- Ionosphere and magnetosphere dynamics
- Geomagnetism and Paleomagnetism Studies
- Magnetic Field Sensors Techniques
- Solar and Space Plasma Dynamics
- Earthquake Detection and Analysis
- Atomic and Subatomic Physics Research
- Inertial Sensor and Navigation
- Sensor Technology and Measurement Systems
- Spacecraft Design and Technology
- Astro and Planetary Science
- Geophysics and Gravity Measurements
- Non-Destructive Testing Techniques
- Atmospheric Ozone and Climate
- Geophysical and Geoelectrical Methods
- Magnetic Properties and Applications
- GNSS positioning and interference
- Statistical and numerical algorithms
- Spacecraft and Cryogenic Technologies
- Rocket and propulsion systems research
- Occupational health in dentistry
- Lightning and Electromagnetic Phenomena
- Aerospace Engineering and Energy Systems
- Plasma Diagnostics and Applications
- Nuclear Physics and Applications
- Medical Malpractice and Liability Issues
University of Iowa
2017-2025
University of Alberta
2013-2020
United States Air Force Academy
2002
High-resolution in situ measurements from the three Swarm spacecraft, a string-of-pearls configuration, provide new insights about combined role of flow channel events and particle impact ionization creating $\textit{F}$ region electron density structures northern Scandinavian dayside cusp. We present case polar cap patch formation where reconnection-driven low-density relative westward is eroding solar-ionized plasma but cusp dominates initial structuring. In cusp, features are observed...
Abstract In situ magnetic field measurements are critical to our understanding of a variety space physics phenomena including field‐aligned currents and plasma waves. Unfortunately, high‐fidelity magnetometer often degraded by stray fields from the host spacecraft, its subsystems, other instruments. One dominant source interference on many missions reaction wheels—spinning platters varying rates used control spacecraft attitude. This manuscript presents novel approach mitigation wheel aboard...
Field-aligned currents couple energy between the Earth's magnetosphere and ionosphere are responsible for driving both micro macro motions of plasma neutral atoms in regimes. These believed to be a contributing source ion acceleration polar may detected via measurements magnetic gradients along track orbiting spacecraft, usually north-south east-west field component. The detection such does not require observatory class geomagnetic field. Magnetic Field instrument (MGF) measures local...
Abstract Difficulty in making low noise magnetic measurements is a significant challenge to the use of cube‐satellite (CubeSat) platforms for scientific constellation class missions study magnetosphere. Sufficient resolution required resolve three‐dimensional spatiotemporal structures field variations accompanying both waves and current systems nonuniform plasmas controlling dynamic magnetosphere‐ionosphere coupling. This paper describes design, validation, test flight‐ready, miniature,...
Abstract High‐resolution multispacecraft Swarm data are used to examine magnetosphere‐ionosphere coupling during a period of northward interplanetary magnetic field (IMF) on 31 May 2014. The observations reveal prevalence unexpectedly large amplitude (>100 nT) and time‐varying perturbations the polar passes, with especially being associated large‐scale downward field‐aligned currents. Differences between measurements sampled at 50 Hz from A C, approximately 10 s apart along track,...
Abstract. Fluxgate magnetometers are important tools for geophysics and space physics, providing high-precision magnetic field measurements. magnetometer noise performance is typically limited by a ferromagnetic element that periodically forced into saturation to modulate, or gate, the local field. The parameters control intrinsic of remain poorly understood. Much basic research producing low-noise fluxgate sensors was completed in 1960s military purposes never publicly released. Many modern...
Abstract The electrodynamics associated with dual discrete arc aurora antiparallel flow along the arcs were observed nearly simultaneously by enhanced Polar Outflow Probe (e‐POP) and Swarm A C spacecraft. Auroral imaging from e‐POP reveals 1–10 km structuring of arcs, which move evolve on second timescales confound traditional single‐spacecraft field‐aligned current algorithms. High‐cadence magnetic data show Hz, inferred Alfvénic, perturbations coincident at same scale size as dynamic...
Abstract The ACES‐II Low sounding rocket, which launched from Andøya Space Center in Andenes, Norway, on 20 November 2022, made low altitude observations consistent with characteristics of the Ionosphere Feedback Instability (IFI) as it traversed a quiet, discrete auroral arc. Small scale Alfvénic signatures are observed regions depleted ionospheric plasma density, large perpendicular electric fields, and matched Pedersen Alfvén conductivities—all observational preconditions required for...
This work discusses the application of a generalizable technique, based on computationally inexpensive statistical and machine learning methods, for rapid identification geophysical events in large observational datasets. Specifically, Dynamic Principal Components Analysis (D-PCA) One-Class Support Vector Machines (OC-SVMs) are used to generate an alternative representation time series inputs, which is subsequently clustered identify outliers. Preliminary studies utilizing this technique...
Unlike the vast majority of astrophysical plasmas, solar wind is accessible to spacecraft, which for decades have carried in-situ instruments directly measuring its particles and fields. Though such measurements provide precise detailed information, a single spacecraft on own cannot disentangle spatial temporal fluctuations. Even modest constellation though capable characterizing fluctuations at one or more scales, fully determine plasma’s 3-D structure. We describe here concept new mission,...
Abstract. CASSIOPE/e-POP, now known as Swarm-Echo, was launched in 2013 to study polar plasma outflow, neutral escape, and the effects of auroral currents on radio propagation ionosphere. The e-POP suite contains an array eight instruments, including two fluxgate magnetometers a shared boom. Until now, relied set preflight calibrations, which limited accuracy magnetic field product magnetometers' utility for some applications. Here we present results situ calibration performed data from 3...
Magnetic interference from the spinning reaction wheels often used to control spacecraft orientation is a well-known issue for accurate sensing of geophysical measurements using sensitive magnetometers that capture magnetic fields in macroscale (order 1 km or greater). Disentangling wheel background has been an open challenge geomagnetic signal analysis several decades. In this letter, we address as feature separation problem and leverage informational redundancy continuity across multiple...
Heavy (O+) ion energization and field-aligned motion in near the ionosphere are still not well understood. Based on observations from CASSIOPE Enhanced Polar Outflow Probe (e-POP) at altitudes between 325 km 730 over one year, we present a statistical study (24 events) of heating its relation to bulk flow velocity, low-frequency waves currents (FACs). The temperature velocity derived 2-D distribution functions measured by suprathermal electron imager (SEI) instrument. Consistent...
Abstract. Accurate high-precision magnetic field measurements are a significant challenge for many applications, including constellation missions studying space plasmas. Instrument stability and orthogonality essential to enable meaningful comparison between disparate satellites in without extensive cross-calibration efforts. Here we describe the design characterization of Tesseract – fluxgate magnetometer sensor designed low-noise, high-stability applications. Tesseract's takes advantage...
Abstract Robust in situ magnetic field measurements are critical to understanding the various mechanisms that couple mass, momentum, and energy throughout our solar system. However, spacecraft on which magnetometers often deployed contaminate via onboard subsystems including reaction wheels magnetorquers. Two can be at different distances from determine an approximation of interfering for subsequent removal, but constant data streams both impractical due power telemetry limitations. Here we...
Abstract. Ongoing innovation in next generation fluxgate magnetometry is important for enabling future investigations of space plasma, especially multi-spacecraft experimental studies energy transport the magnetosphere and solar wind. Demonstrating spaceflight capability novel designs an step instrument development process; however, large-scale satellite missions are often unwilling to accept risks without flight heritage. The Tesseract – a magnetometer sensor design-had opportunity...
Abstract. Fluxgate magnetometers are commonly used to provide high-fidelity vector magnetic field measurements. The noise of the measurement is typically dominated by that intrinsic a ferromagnetic core modulate (gate) local as part fluxgate sensing mechanism. A polycrystalline molybdenum–nickel–iron alloy (6.0–81.3 Mo permalloy) has been in fluxgates since 1970s for its low noise. Guided previous investigations high-permeability copper–nickel–iron alloys, we investigate alternative...
Abstract. Space-based measurements of Earth's magnetic field are required to understand the plasma processes responsible for energising particles in Van Allen radiation belts and influencing space weather. This paper describes a prototype fluxgate magnetometer instrument developed proposed Canadian Space Agency's (CSA) Outer Radiation Belt Injection, Transport, Acceleration Loss Satellite (ORBITALS) mission which has applications other suborbital applications. The is designed survive operate...
Abstract. Fluxgate magnetometers are commonly used to provide high-fidelity vector magnetic field measurements. The noise of the measurement is typically dominated by that intrinsic a ferromagnetic core modulate (gate) local as part fluxgate sensing mechanism. A polycrystalline molybdenum-nickel-iron alloy (6.0–81.3 Mo Permalloy) has been in fluxgates since 1970s for its low noise. Guided previous investigations high permeability copper-nickel-iron alloys, we investigate alternative...
Abstract. Fluxgate magnetometers are an important tool in geophysics and space physics but typically sensitive to variations sensor temperature. Changes instrumental gain with temperature, thermal dependence, thought be predominantly due changes the geometry of wire coils that sense magnetic field and/or provide feedback. Scientific fluxgate employ some form temperature compensation support constrain bobbins constructed from materials such as MACOR machinable ceramic (Corning Inc.) which...
Abstract The fundamental processes responsible for energy exchange between large-scale electromagnetic fields and plasma are well understood theoretically, but in practice these theories have not been tested. These ubiquitous all plasmas, especially at the interface high low beta plasmas planetary magnetospheres other magnetic environments. Although such boundaries pervade Universe, release of stored thermal fully identified importance relative impact each process is unknown. Despite...
Abstract. Magnetometer measurements are one of the critical components necessary to improve our understanding intricate physical processes coupling mass, momentum, and energy within near-Earth space throughout solar system. However, these often contaminated by stray magnetic fields from spacecraft hosting field sensors, data requires application interference mitigation algorithms prior scientific use. Rigorous numerical validation techniques can be challenging when they applied in-situ...
In-situ spacecraft observations are critical to our study and understanding of the various phenomena that couple mass, momentum, energy throughout near-Earth space beyond. However, on-orbit telemetry constraints can severely limit capability transmit high-cadence data, missions often only able telemeter a small percentage their captured data at full rate. This presents programmatic need prioritize intervals with highest probability enabling mission’s science goals. Larger such as...