Browsing by Author "Reshid, Remudin ( PhD)"

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    Decay of Pulsar's Magnetic fields Via Neutrino Emission Processes
    (Addis Ababa University, 2017-10) Bezabh, Tsegay; Reshid, Remudin ( PhD)
    Currently, there is no clear understanding of how pulsar magnetic elds decay. This is the motivation behind the development of this particular model for pulsar eld dissipation. In this work we develop a theoretical model for surface magnetic elds of neutron stars (NSs) based on spinning separated charges that arise as a result of plasma di usion processes inside NS matter [1]. As was described in this model, we have pointed out that such kinds of magnetic elds will be temperature dependent, and should decay primarily as a result of neutrino emissions. In this work we have formulated magnetic eld decay law associated with neutrino emission process correspondingly the NSs cooling curve. Based on the above model, the magnetic eld derived from this law is shown to be consistent with observations from typical young pulsars, like crab and vela young ones. We have also explored the possible implications of the results such as the observed variations and possible time evolution of pulsar braking indices are also discussed
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    Infinite Magnetic Poles of Pulsars
    (Addis Ababa University, 2017-09) Belay, Dugasa; Reshid, Remudin ( PhD)
    The recent observations and theory indicates that the presence of in nite non-dipolar pulsars magnetic elds, it has become more and more clear that pulsars posses magnetic eld structure, which are much more complicated than the simple assumption of dipolar pulsars magnetic elds. In this work, we analyze the presence of in nite non-dipolar com- ponents of the pulsar magnetic eld, as derived from a recent model. We derived both the dipolar and in nite non-dipolar components of the eld separately. We have approached the problem by applying post-Newtonian approximation, to nd the in nite non-dipolar pulsar magnetic eld. Among in nite non-dipolar components of pulsar's magnetic eld, we have both derived the expression for quadrapole and octupole component of the mag- netic eld and studied their implication