Simulating the driven magnetosphere

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dc.contributor.advisorToffoletto, Frank R.en_US
dc.creatorLemon, Colby Leeen_US
dc.date.accessioned2009-06-04T08:27:12Zen_US
dc.date.available2009-06-04T08:27:12Zen_US
dc.date.issued2005en_US
dc.description.abstractA significant effort is focused on understanding the behavior of the Earth's magnetosphere during times of southward interplanetary magnetic field, when the magnetosphere is in a driven state. In situ observations of the space environment provide us with real magnetic and electric field and plasma data with which to study magnetospheric processes, yet we lack the ability to experimentally control the parameters that influence these processes. On the other hand, a niche of computational modeling is the ability to experiment with these parameters in a straightforward effort to understand the magnetospheric response. The simulation model employed in this thesis (the Rice Convection Model-Equilibrium, or RCM-E) is unique in its ability to calculate the energy dependent drifts of plasma particles as well as their feedback on both the electric and magnetic fields. Three different RCM-E simulations are presented. First, the magnetospheric response to a moderate level of external driving is modeled, showing that the model reproduces several of the features of steady magnetospheric convection (SMC) events. The simulation is then repeated with a more rigorous calculation of the magnetic field that generally produces a higher quality result but suffers from excessive numerical noise in the important inner plasma sheet region. This simulation produces a more stressed magnetic field, but encounters numerical breakdown due largely to the numerical noise. The proper response to steady driving in the RCM-E is likely to be more stressed than the first simulation, yet more stable than the second simulation. Somewhat counter to conventional wisdom, these simulations suggest that enhanced convection by itself is insufficient to inject a ring current, since the magnetic field response acts to mitigate the injection. In the third simulation, a method for injecting plasma into the ring current without drastically affecting the near-Earth magnetic field configuration is demonstrated: significantly reduce the specific entropy of the injection source. The steady driving simulations apparently failed to produce a realistic ring current injection because the model equations conserve specific entropy as plasma is transported (adiabatic transport). These simulations suggest that a non-adiabatic plasma process---possibly the substorm---plays an important role in the dynamics of geomagnetic storms.en_US
dc.format.extent147 p.en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.callnoTHESIS PHYS. 2005 LEMONen_US
dc.identifier.citationLemon, Colby Lee. "Simulating the driven magnetosphere." (2005) Diss., Rice University. <a href="https://hdl.handle.net/1911/18851">https://hdl.handle.net/1911/18851</a>.en_US
dc.identifier.urihttps://hdl.handle.net/1911/18851en_US
dc.language.isoengen_US
dc.rightsCopyright 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.subjectPlasma physicsen_US
dc.titleSimulating the driven magnetosphereen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentPhysicsen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
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