Date of Award
2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Space Science
Committee Chair
Lingling Zhao
Committee Member
Gary P. Zank
Committee Member
Jakobus Le Roux
Committee Member
Laxman Adhikari
Committee Member
Alexander Pitňa
Research Advisor
Lingling Zhao
Subject(s)
Particle acceleration, Heliosphere (Astrophysics), Solar wind, Magnetohydrodynamics
Abstract
Stream Interaction Regions (SIRs) play a critical role in energetic particle acceleration and transport in the heliosphere. While shocks and compression regions associated with SIRs can accelerate particles to several MeV energies, most of our current understanding of these events is based on observations near 1 AU and beyond. Observations inside 1 AU, particularly by PSP and SolO, provide a unique opportunity to disentangle the roles of acceleration and transport. This dissertation presents the first detailed measurements of SIR-associated energetic particle events in the inner heliosphere between 0.15 and 0.80 AU using PSP, complemented by SolO and multi-spacecraft observations near 1 AU. The events are relatively weak without shocks, yet still show localized suprathermal and energetic particle enhancements. Spectra reveal hardening below 1 MeV, softening above 1 MeV, and no low-energy turnover, pointing to efficient local acceleration at compression regions. This work utilizes observations from PSP, SolO, STEREO-A, ACE, and Wind. This research was supported by NASA-HELIO-FINESST Grant 80NSSC24K1867.
Recommended Citation
Silwal, Ashok, "Multipoint observations of energetic particle acceleration associated with corotating interaction regions" (2025). Dissertations. 469.
https://louis.uah.edu/uah-dissertations/469