Author ORCID Identifier
0000-0001-6137-8814
Document Type
Dissertation
Date of Award
5-31-2023
Degree Name
Doctor of Philosophy in Applied Physics - (Ph.D.)
Department
Physics
First Advisor
Andrew Gerrard
Second Advisor
Dale E. Gary
Third Advisor
Bin Chen
Fourth Advisor
Gareth Perry
Fifth Advisor
Hyomin Kim
Sixth Advisor
Nathaniel A. Frissell
Abstract
The mechanisms whereby low energy (order of lOs to 100s of eV) solar wind and ionosphere sourced particles are accelerated to high energy (order of 10s to 100s keV) in the Earth's magnetosphere are a trending research topic due to impacts on radiation belt populations, coupling to the high-latitude ionosphere, and energy budgets for collision-less plasma in dipole fields. Ultra-low frequency (ULF, order of 1-100 mHz) Alfven waves observed in the nightside inner magnetosphere during geomagnetic activity are one such acceleration mechanism. Several source processes for these waves, including the micro-scale drift-mirror mode, have been previously suggested but observational evidence is limited. The likelihood of drift-mirror mode formation depends on the strength of non-Maxwellian deformations in the particle distribution, but knowledge of the extent of these deformations in the inner magnetosphere is also limited.
The first half of this dissertation is a climatological investigation of the likelihood of drift-mirror mode formation in the inner magnetosphere utilizing particle distributions measured by the NASA Van Allen Probes Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) particle detector. The second half investigates the morphology of measured quiet-time particle distributions of RBSPICE through fitting a model single-population distribution function which captures both Maxwellian and deformed-Maxwellian distribution features. These fits are utilized to create a distributable empirical background flux model with applications in both drift-mirror mode and satellite engineering radiation dosage models.
The first investigation confirms previous determinations of the plasma in the dusk-to-midnight sector being unstable to the drift-mirror mode and shows it to occur exclusively during times of high Dst. It also finds the identification of drift-mirror modes utilizing particle distributions is not well-quantified and requires knowledge of the background distribution's morphology. The fitting results of the second study determine quiet time inner magnetospheric distributions commonly exhibit deformed Maxwellian characteristics. Unexpected results of this investigation are a surprising number of quiet time measurements not representable by a single-population thermodynamic distribution function either because of non-statistical features of the distribution or the presence of multiple particle populations. The unique approach of the background flux model is suggested as a modification to current engineering model frameworks.
Recommended Citation
Cooper, Matthew, "Large-scale and meso-scale ion dynamics of the near-earth space environment" (2023). Dissertations. 1819.
https://digitalcommons.njit.edu/dissertations/1819
