Date of Award
2025
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Space Science
Committee Chair
Nikolai Pogorelov
Committee Member
Alphonse Sterling
Committee Member
Laxman Adhikari
Committee Member
Qiang Hu
Committee Member
Vladimir Florinski
Research Advisor
Tae Kim
Subject(s)
Solar wind, Magnetohydrodynamics, Space environment--Forecasting
Abstract
The solar wind (SW) is a vital component of space weather (SWx), providing a background for solar transients such as coronal mass ejections, stream interaction regions, and energetic particles propagating toward Earth. Accurate prediction of SWx events requires a precise description and thorough understanding of physical processes occurring in the ambient SW plasma. This dissertation investigates the effect of uncertainty associated with solar photospheric boundary conditions (BCs) on magnetohydrodynamic (MHD) simulations of the SW in the inner heliosphere. For this purpose, I perform ensemble simulations of the three-dimensional SW flow using an empirically-driven MHD heliosphere model implemented in the Multi-Scale Fluid-Kinetic Simulation Suite (MS-FLUKSS). The key aspect of the work is the multipoint validation of the ensemble model of the SW using in situ SW plasma and magnetic field data from the Parker Solar Probe, Solar Orbiter, Solar Terrestrial Relations Observatory-A (STEREO-A), and near-Earth observations. I approached the problem in three steps. Firstly, the level of uncertainty and performance of the ensemble model in capturing large-scale SW structures are examined through a qualitative comparison of the simulation results with multi-spacecraft observations. Secondly, the model's performance is evaluated and associated uncertainties are quantified using a comprehensive quantitative framework that involves multiple validation metrics, variables, inner heliospheric locations, and time periods. Finally, the work assesses the model capabilities in reproducing the SW stream interaction regions (SIRs). It analyzes the effect of uncertainties in the photospheric BCs on the simulation results at Earth and STEREO-A. The presented simulation results are in good overall agreement with the observational data at multiple points in the inner heliosphere. This dissertation represents the first systematic multi-spacecraft investigation of quantified uncertainties in SW simulations arising from time-dependent photospheric BCs. This makes it possible to shed more light on the properties of the SW propagating through the heliosphere and perspectives for improving SWx forecasts.
Recommended Citation
Hegde, Dinesha Vasanta, "Modeling solar wind in the inner heliosphere with quantified uncertainties" (2025). Dissertations. 464.
https://louis.uah.edu/uah-dissertations/464