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Please use this identifier to cite or link to this item: http://hdl.handle.net/10805/2179

Title: Kinetic approach to pair production in strong electric fields and to transparency of relativistic outflows
Authors: BENEDETTI, ALBERTO
Tutor: Vereshchagin, Gregory
Issue Date: 14-Nov-2013
Description: In my thesis I present the theoretical study of two physical phenomena in plasma physics, namely (a) electron-positron pairs production in strong electric fields and (b) transparency of relativistic outflows. From the theoretical point of view, both these systems have been long under study. The pair production due to Schwinger effect is one of the key problems in modern Quantum Field Theory. Currently an international effort is underway aiming at generation of ultrahigh intensities of laser fields and thereby creating electric fields near the critical value for the pair production. There is an ongoing debate on whether the critical electric field can be potentially reached in these experiments. In the literature many theoretical studies of pair production can be found. However very few of them account for back reaction of created pairs on the initial electric field. Concerning transparency of relativistic outflows, there is currently a consensus in the literature that emission produced by the photosphere of relativistically expanding plasma should be present in all gamma-ray bursts (GRBs). The intensity of this photospheric component emission may be weak compared to the total intensity of the GRB. However when detected, this emission may provide unique information on physical properties of relativistic outflows which produce GRBs. Even though very different in what concerns their macroscopic features, the microphysics of both phenomena (a) and (b) can be described in detail using a common method. This is what we aim to do in the study of pairs creation and photospheric emission using a theoretical approach based on Relativistic Kinetic Theory (RKT). One of the main motivations behind this strategy is related to the possibility, given by such theory, to study physical systems out of equilibrium from a very general point of view. To do that we solve the Relativistic Boltzmann Equation (RBE) with exact collision integrals corresponding to relevant microscopic processes, taking into account the anisotropy of the distribution function in the phase space. One one hand, with this technique we are able to describe the evolution in time of the initially out of equilibrium system of electric field and electron-positron-photon plasma up to thermalization. On the other hand when transparency of relativistic outflow is considered, the opposite behavior of departure of electron-photon plasma from thermal equilibrium can be followed.
URI: http://hdl.handle.net/10805/2179
Research interests: Theoretical physics, Astrophysics
Personal skills keywords: Theoretical physics
Astrophysics
Mathematical modeling
Programming
Fluent english
Appears in PhD:ASTROFISICA RELATIVISTICA, IRAP-PHD

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