Fate Of Gravitational Collapse In Electromagnetic Theory

In this thesis, we address the issue of gravitational collapse in electromag- netic theory.For this purpose, we adopt two approaches one by assuming charged perfect fuid in the interior of a star and another by studying the dynamics of thin shell of matter on the surface of a charged star.The cylindrically symmetric charged perfect fuid collapse is explored by assum ing that charged perfect fluid is moving along geodesics in the interior of cylinder.In this case, the analytic solution of the Einstein-Maxwell eld equations represents gravitational collapse.The end state of collapse is found to be conical singularity.We formulate general dynamical equations using Israel thin shell formal- ism in charged background which helps to investigate gravitational collapse of scalar eld and polytropic matter thin shell. In massless case, we find that scalar shell either expands to in�nity or collapses to a point forming a curvature singularity.Also, the massive scalar eld shell can exhibit the bouncing behavior.It is found that expanding and collapsing polytropic matter as well as perfect �uid shell comes to rest, then re-expands to innfinity or re-collapses to a point. We also discuss the polytropic matter collapse in non-commutative geometry.The non-commutative parameter stops the shell to expand or collapse again, so there occurs a singularity at non-zero value of shell radius.The charged perfect �uid collapse with positive cosmological constant is investigated in Friedmann and 5D Tolman-Bondi models. We nd mar ginally bound solution for both models and non-marginally bound solution for 5D model.Also, the formation of apparent horizons is discussed.The end state of charged perfect fluid gravitational collapse in both models has been found as a black hole. Finally, we discuss phantom energy accretion onto a 5D charged black hole. It is found that if the charge of black hole is larger than its mass, then a black hole is converted into naked singularity.The critical accretion points are investigated. We conclude that when phantom energy accretes onto 5D charged black hole then there appears a mass to charge ratio, the lower limit of this ratio represents a regular as well as extremal 5D charged black holes, while upper limit represents a naked singularity