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Accretion onto charged black holes

The discovery of active galactic nuclei and quasars as well as compact objects like supermassive black holes, neutron stars and pulsars prompted the realisation that their high energy emission was due to the liberation of the gravitational potential energy of in- falling material. Bondi accretion models a polytrope fluid accelerating towards a star with a Newtonian gravitational potential. This was later extended to full general relativity by Michel who examined accretion onto a Schwarzschild black hole. Modelling accreting systems in full general relativity becomes signifi icantly more challenging when one includes more realistic phenom- ena like viscosity, magnetic elds, turbulence and radiative processes. Paczynski and Wiita introduced a gravitational potential that approx- imates many features of the Schwarzschild black hole in general rela- tivity. The system's dynamical behaviour is governed by the Navier- Stokes equations which are substantially simpler to analyse than those arising from a full relativistic treatment. In this project we will derive a pseudo-Newtonian potential for the Reissner-Nordstrom metric following a recently discovered algorithm. We will then solve the problem of matter accreting onto a charged black hole. This project encompasses aspects of fluid mechanics, Newtonian gravity, astrophysics and general relativity. The techniques employed will be largely analytical with some numerical methods like root finding and curve sketching.
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Requirements for students to address: 
Knowledge of advanced calculus, differential equations and electromagnetic theory is essential. Aspects of fluid mechanics and general relativity will be developed throughout the course of the project.
Research Area: 

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