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|Title:||Outbursts and instabilities of massive accretion discs|
|Presented at:||University of Leicester|
|Abstract:||This thesis consists of 4 chapters with chapter 1 introducing the science and chapter 2 the numerical methods used in chapters 3 and 4. Chapter 3 focuses on outbursts of the galactic microquaser GRS1915+ 105. I investigate the effect of various parameters on the outburst shape and variability using 3d SPH (Smooth Particle Hydrodynamics) Simulations. For reasons of computational time/power some parameters need to be scaled up/down from the true values and I include a new method of predicting outburst/recurrence times and duty cycles from simulation results based on these scalings. Typically I find a duty cycle which 25 for simulations with a mean irradiation radius of ().2 . where a is the binary separation. Discs with periods somewhat longer 5 years) orbital periods than GRS1915 can become self gravitating. Chapter 4 is preliminary work on extending the simulations of chapter 3 to include the effects of self gravity, but is sufficiently general to be applicable to self-gravitating discs in many other contexts. The main part of chapter 4 is an investigation of the effect of self gravity on the evolution of a viscous ring of matter. The numerical simulations in chapter 4 are performed using a new code, SPHfalcON which I helped develop.|
|Rights:||Copyright © the author. All rights reserved.|
|Appears in Collections:||Theses, Dept. of Physics and Astronomy|
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