Magnetic Compton scattering in pulsar magnetospheres
| dc.contributor.advisor | Michel, F. Curtis | en_US |
| dc.creator | Sturner, Steven John | en_US |
| dc.date.accessioned | 2009-06-04T00:25:36Z | en_US |
| dc.date.available | 2009-06-04T00:25:36Z | en_US |
| dc.date.issued | 1993 | en_US |
| dc.description.abstract | In the large magnetic fields associated with highly magnetized neutron stars, the Compton cross section exhibits a resonance at the local cyclotron energy. In this work I describe applications of magnetic Compton scattering to models of both rotation powered and accretion powered pulsars. Radio pulsars are generally considered to be rapidly rotating, highly magnetized neutron stars. The rapid rotation coupled with the large magnetic field induces large electric fields that can accelerate electrons in the neutron star magnetosphere to large energies. I have produced a Monte Carlo code to model $\gamma$-ray emission from rotation powered pulsars utilizing pair cascades initiated by Comptonized photons. Previous polar cap $\gamma$-ray emission models have relied on pair cascades initiated by curvature radiation photons. This Monte Carlo model can reproduce the double peak pulse profiles often observed from rotation powered pulsars and explain the trend for harder spectra from slower pulsars. X-ray Pulsars are thought to be highly magnetized neutron stars accreting matter from an ordinary stellar companion. The accreting matter is channeled onto the neutron star polar cap by the magnetic field. This material produces a hot spot on the neutron star surface that emits X-rays. I have investigated the effects of radiation pressure due to these X-rays on the accreting material. The radiation pressure is greatly enhanced by the resonance in the magnetic Compton cross section. Because the electron cyclotron energy varies with distance from the neutron star, the energy dependent X-ray spectrum maps to a spatially varying radiation force. This force can exceed the force of gravity over a limited region of the X-ray pulsar magnetosphere. I postulate that when this occurs matter can be elevated above the neutron star surface outside the accretion column. This material will act as an energy dependent "lamp shade" that will produce pulse profiles that vary with photon energy. This model is capable of reproducing the energy dependent pulse profiles observed from the X-ray pulsars 4U 1626-67, 4U 1538-52, 4U 1907+09, and Vela X-1. | en_US |
| dc.format.extent | 144 p. | en_US |
| dc.format.mimetype | application/pdf | en_US |
| dc.identifier.callno | Thesis Sp. Sci. 1993 Sturner | en_US |
| dc.identifier.citation | Sturner, Steven John. "Magnetic Compton scattering in pulsar magnetospheres." (1993) Diss., Rice University. <a href="https://hdl.handle.net/1911/16673">https://hdl.handle.net/1911/16673</a>. | en_US |
| dc.identifier.uri | https://hdl.handle.net/1911/16673 | en_US |
| dc.language.iso | eng | en_US |
| dc.rights | Copyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder. | en_US |
| dc.subject | Astronomy | en_US |
| dc.subject | Astrophysics | en_US |
| dc.title | Magnetic Compton scattering in pulsar magnetospheres | en_US |
| dc.type | Thesis | en_US |
| dc.type.material | Text | en_US |
| thesis.degree.department | Space Science | en_US |
| thesis.degree.discipline | Natural Sciences | en_US |
| thesis.degree.grantor | Rice University | en_US |
| thesis.degree.level | Doctoral | en_US |
| thesis.degree.name | Doctor of Philosophy | en_US |
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