Gravitational and Gravity Waves: the EBEX and PMC Turbo Balloon Experiments

• Main Author: Geach, Christopher
• Format: Thesis
• Language: English
• Published: 2020
• Subjects: Canada; Antarc*; Antarctica
• Online Access: https://hdl.handle.net/11299/218719

University of Minnesota Ph.D. dissertation. December 2020. Major: Physics. Advisor: Shaul Hanany. 1 computer file (PDF); xviii, 236 pages. I describe my contributions to two balloon-borne experiments in two different fields: the E & B EXperiment (EBEX), a mm-wave polarimeter that flew from Antarctica in 2013 in search of a gravitational wave signature in the cosmic microwave background (CMB); and the Polar Mesospheric Cloud Turbulence (PMC Turbo) experiment, an atmospheric science payload that flew from Sweden to Canada in 2018 in search of a signature of gravity waves in images of polar mesospheric clouds. Gravitational waves in the primordial Universe are predicted to have imprinted a specific pattern in the polarization of the CMB; a detection of this signature would constrain models of inflation. Gravity waves in our atmosphere transport momentum vertically and are an important driver for the circulations and thermal structure of the upper atmosphere. My contributions to EBEX came after flight; I finalized aspects of the spectral and polarization calibration through a combination of analytical derivations and experimental measurements. For PMC Turbo, my role was more encompassing: I was responsible for the mechanical and thermal design of the payload; I developed the post-flight image processing algorithm to calibrate the images and to remove spurious signals; and I developed analysis techniques to identify and characterize gravity waves in the images. This work culminated with a detailed analysis of a particular event in which strong gravity wave breaking was captured in the PMC Turbo images, enabling quantification of the momentum deposition and energy dissipation associated with this event.