Date of Award
Doctor of Philosophy (PhD)
James A. Miller
James H. Adams, Jr.
Jonathan H. Fisher
Solar energetic particles., Solar radiation--Mathematical models.
A new probabilistic model has been presented in the dissertation. The Mission-Specific Solar Radiation Environment Model (MSSREM) peak flux model provides a design reference environment that can be tailored to a specific mission with the mission length, mission duration, and confidence level specified. These reference environments will provide the bounding-case flux for solar energetic particles that will be encountered during the mission at the specified confidence level. The MSSREM peak flux model probabilistically models the environment for six elements (hydrogen, helium, carbon, oxygen, silicon, and iron) and scales these environments to produce the remaining 86 environments for elements Z=1-92. The MSSREM peak flux model uses datasets of particle flux measurements from multiple satellites. These datasets come from a combination of existing datasets and datasets that were produced for the six probabilistically modeled elements in MSSREM. The data for the produced datasets were cleaned and normalized to create continuous datasets. MSSREM uses three different approaches to produce the reference environments, two direct methods and one interpolated method. First, for missions longer than 0.5 years, the MSSREM peak flux model uses extreme value theory that was first described in Xapsos et al. (1998). Second, for missions spanning less than a few days, MSSREM uses a new data-driven modeling approach that allows for unique reference environments to be built for missions as short as 5 minutes. Third, these two approaches can be extrapolated to determine the reference environments for mission lengths between the two approaches. This allows MSSREM to produce reference environments for any mission length. In addition, the MSSREM peak flux model uses the monthly sunspot number to predict the solar activity during the mission rather than the phase of the solar cycle. This allows for the design reference environments to be tailored more closely to the specified mission rather than just the solar minimum or solar maximum of a typical solar cycle. The environments generated by MSSREM are 1 AU away from the Sun and outside the Earth's magnetic field. These environments can then be used with a geomagnetic cutoff transmission function, a trapped radiation model, and a cosmic ray model to provide a complete picture of the bounding case environment for the specified mission.
Robinson, Zachary Donald, "Mission Specific Solar Radiation Environment Model (MSSREM) : peak flux model" (2020). Dissertations. 215.