Author ORCID Identifier
0000-0001-7952-8032
Document Type
Dissertation
Date of Award
5-31-2024
Degree Name
Doctor of Philosophy in Applied Physics - (Ph.D.)
Department
Physics
First Advisor
Hyomin Kim
Second Advisor
Haimin Wang
Third Advisor
Bin Chen
Fourth Advisor
Jason T. L. Wang
Fifth Advisor
Qiang Hu
Sixth Advisor
Li Zhu
Abstract
The solar wind is a plasma constantly blowing out from the Sun with a large-scale magnetic field having significant local complexity at small scales. Small-scale magnetic flux ropes (SMFRs), plasma structures with twisted field lines, are an important element of this complexity. This dissertation contributes several studies that further our understanding of SMFRs. The first study applies machine learning to measurements from Wind labeled by the presence of SMFRs and magnetic clouds (MCs). MCs were distinguished from non-MFRs with an AUC of 94% and SMFRs with an AUC of 89% and had distinctive plasma properties, whereas SMFRs appeared to be nearly indistinguishable from the background solar wind after accounting for the 5 nT threshold applied by the original catalog of SMFRs detected using the automated GS-based algorithm. The second study presents an improved GS detection algorithm used to detect 512,152 SMFRs from 27 years of high-resolution Wind measurements. The SMFR filling factor (~ 35%) is found to be independent of solar activity, distance to the heliospheric current sheet (HCS), and solar wind plasma type after accounting for statistical biases. SMFR diameter is found to follow a log-normal distribution peaking below the resolved range. The third study applies the algorithm to data from Parker Solar Probe, Solar Orbiter, Wind, and Voyager 1 & 2 to detect events from 0.06 au to 10 au. The number of SMFRs with higher axial flux is found to increase significantly with distance from the Sun, suggesting that SMFRs evolve by stochastically merging to produce larger SMFRs. SMFRs were detected in large numbers with log-normally distributed axial flux as close to the Sun as 0.06 au, so it remains unclear whether SMFRs begin their journey as solar eruptions or are continuously generated within the corona and solar wind.
Recommended Citation
Farooki, Hameedullah, "On the ubiquity, properties and evolution of small-scale magnetic flux ropes in the heliosphere" (2024). Dissertations. 1755.
https://digitalcommons.njit.edu/dissertations/1755
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Astrophysics and Astronomy Commons, Fluid Dynamics Commons, Other Physics Commons, Plasma and Beam Physics Commons
