The Double Beltrami model of coronal mass ejections

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dc.contributor.advisorKumar, Pawan
dc.contributor.advisorMahajan, Swadesh M.
dc.creatorKagan, Daniel Ross
dc.date.accessioned2017-03-31T14:58:48Z
dc.date.available2017-03-31T14:58:48Z
dc.date.issued2007-08
dc.description.abstractCoronal mass ejections (CMEs) are the most powerful events on the Sun and have important effects on Earth (geomagnetic storms), but their initiation is still not well understood. I show that the general class of Double Beltrami states, which are the lowest energy equilibria of Hall magnetohydrodynamics, can have characteristics similar to those of CME source regions in the solar corona and are capable of undergoing a catastrophe that can supply enough kinetic energy to create a CME. I then compare this Double Beltrami model of CMEs with observations. First, I show that the qualitative evolution of the DB state is consistent with that of a CME. Second, I carry out a detailed quantitative study of the expansion of the field during the quasi-equilibrium stage leading up to the catastrophe using LASCO C1 CME data, confirming the model prediction of an expansion of a factor of 1-2 in the height of the CME leading edge before major acceleration begins. Finally, I use the assumption that DB states are randomly chosen from the allowed phase space of coronal structures to predict the CME rate from the rate at which DB states appear. Taking each active region as having a corresponding DB state and using observational constraints to estimate that the state is replaced every 60 minutes by emerging loops results in a CME rate of 19.5 per day, which is in reasonable agreement with the actual rate of 6 per day at solar maximum (systematic uncertainties may be responsible for the differences that do exist). Future work for the dissertation will involve improvements leading up to a full simulation of the DB model including heat transfer, and the application of the model to stars and accretion disks.en_US
dc.description.departmentAstronomyen_US
dc.format.mediumelectronicen_US
dc.identifierdoi:10.15781/T22J6892S
dc.identifier.urihttp://hdl.handle.net/2152/46289
dc.language.isoengen_US
dc.relation.ispartofUT Electronic Theses and Dissertationsen_US
dc.rightsCopyright © is held by the author. Presentation of this material on the Libraries' web site by University Libraries, The University of Texas at Austin was made possible under a limited license grant from the author who has retained all copyrights in the works.en_US
dc.rights.restrictionRestricteden_US
dc.subjectCoronal mass ejections (CMEs)en_US
dc.subjectDouble Beltrami (DB) modelen_US
dc.subjectGeomagnetic stormsen_US
dc.titleThe Double Beltrami model of coronal mass ejectionsen_US
dc.typeThesisen_US
dc.type.genreThesisen_US
thesis.degree.departmentAstronomyen_US
thesis.degree.disciplineAstronomyen_US
thesis.degree.grantorUniversity of Texas at Austinen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Artsen_US

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