| dc.description.abstract | The non-detection of an electromagnetic cascade in the electron-positron plasma
beams from blazars has led many physicists to invoke an intergalactic magnetic
eld that de
ects charged particles away from our eld of view. In this thesis we
look at a dierent explanation. Namely that the beams loose their energy through
plasma instabilities rather than the inverse Compton scattering which would create
the cascade. We use a covariant formalism to calculate the linear response tensor
of the plasma. Using this tensor we nd the absorption coecient for particles
distributed according to the Jüttner distribution and for a dierent distribution
based on simulations. The absorption coecient is found to diverge for specic
values of the phase velocity when the electric eld of the mode vanishes. This is
unphysical, which means there is some issue with the calculations. The issue is
identied as the assumption that the imaginary part of the frequency, known as the
absorption coecient, is small. This assumption contradicts the results making the
calculations invalid. To solve this problem one would have to redo the calculations
avoiding this assumption. | |
