Abstract

Fast radio bursts (FRBs) are millisecond-duration radio bursts with applications as cosmic probes. However, their physical origins remain largely unknown. Magnetars are natural candidates for producing FRBs due to their compact size, extremely strong magnetic fields, and intrinsically dynamic nature. In this thesis, I develop a model for FRB production grounded in both a concrete triggering mechanism and a viable emission process. This process begins by launching low-frequency plasma waves into the magnetosphere. I show that energetic fast magnetosonic waves can naturally be produced in the magnetosphere, independent of how these waves are launched. Regardless of whether these waves are launched directly from the star, or produced indirectly from mode conversion, these fast waves can steepen into extremely powerful shocks. Potentially the strongest shocks in the universe, these `monster shocks' have an exciting connection to FRBs. They create a coherent precursor wave that propagates ahead of the shock with properties suggestive of fast radio bursts, while the shock heated plasma will cool and may contribute to the X-ray counterpart seen with the galactic FRB. I present the results of first-principles kinetic simulations of the nonlinear evolution of these fast magnetosonic waves in a realistic magnetosphere. Using these simulations, I confirm the extreme scaling relation responsible for the term ‘monster shocks’ and extend these predictions to the global magnetospheric structure. I quantify the global structure of these shocks, as well as the intrinsic angular anisotropy of their emission. Finally, I discuss the implications these properties may have for FRB observations.

Committee Chair

Yajie Yuan

Committee Members

Alexander Chen; Bart Ripperda; James Buckley; Manel Errando

Degree

Doctor of Philosophy (PhD)

Author's Department

Physics

Author's School

Graduate School of Arts and Sciences

Document Type

Dissertation

Date of Award

6-19-2026

Language

English (en)

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