Baring, Matthew G.2014-08-042014-08-042014-052014-04-16May 2014Barchas, Joseph. "Electrostatic Energy Exchange in Shock Acceleration." (2014) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/76350">https://hdl.handle.net/1911/76350</a>.https://hdl.handle.net/1911/76350Plasma shocks are very common occurrences, and diffusive shock acceleration is a simple and efficient mechanism for generating cosmic rays. A shock's main effect is turbulent dissipation, which rapidly thermalizes the downstream plasma. Diffusive shock acceleration produces a non-thermal component to the particle distributions (quasi-power-law tails) which translates to non-thermal photon spectra, as seen in supernova remnants, jets in active galactic nuclei, and gamma-ray bursts. In supernova remnants, X-ray observations show that inferred proton temperatures are considerably cooler than standard shock heating predicts. A cross-shock electrostatic potential, akin to a double layer, is reasoned to exist in certain conditions due to the different inertial gyration scales of the plasma species. It provides a mechanism for energy exchange between species, and should result in a respective heating/cooling of the electrons/ions. It modifies the electron/ion distributions, which couple through radiative processes to the observed X-ray emission. In this thesis, the effects of cross-shock electrostatics are explored using a Monte Carlo simulation, where test particles gyrate and stochastically diffuse in a background fluid pre-defined by MHD jump conditions.A cross-shock electric field is derived from the steady-state spatial distribution of particles via a modified Poisson's equation that includes Debye screening, and the simulation is rerun with this field superimposed on the background magnetic and drift electric fields. This feedback loop continues until a self-consistent solution is obtained. Results show a significant departure of the particle distributions from the usual thermal+power-law form, and clearly demonstrates substantial energy exchange between the electron and ion populations.application/pdfengCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.Shock accelerationMonte CarloThesis2014-08-04