Magnetic perturbations due to current structural variations

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dc.contributor.advisorCloutier, Paul A.en_US
dc.creatorTeng, Yuan-Chengen_US
dc.date.accessioned2018-12-18T21:14:53Zen_US
dc.date.available2018-12-18T21:14:53Zen_US
dc.date.issued1974en_US
dc.description.abstractStudy of the magnetic perturbations caused by auroral currents has been conducted by rocket-borne magnetometer measurements for years. Since the horizontal auroral currents were usually found to be confined near the visible auroral arcs, as determined by Heppner [1954], Davis [1961], and Davis and Kimball [1962], a number of current models have been established in order to explain observed data by rockets or satellite measurements. In those models, the requirement that the current be continuous across the highly conducting arc results in either polarization electric fields to reduce the current in the highly conducting region or Birkeland currents to provide return current to the outer part of the magnetosphere. Bostrom found two basic solutions, one in which a horizontal electrojet connects two filamentary Birkeland currents, and the other in which broad Birkeland sheet currents (Fig. 2) flow to the edges of the arc, with a transverse closing current and a Hall electrojet. In this thesis, we adopted a model similar to the second solution and assumed that the arc was bombarded by energetic precipitating electrons. In this thesis, the effect of a spatial fold on the magnetic vector field in the vicinity of the arc is examined. Fig. 1 shows the current model used in the initial calculations. It has a displacement of thickness of 3 km from its center and is composed of two current parts. One part is the two oppositely directed Birkeland sheet currents having an equal current density of .5 amp/m and an equal thickness of 3 km for each sheet, in which the downward current sheet is on the south side of the arc and the upward on the north. And the 3 other part is an electrojet having a magnitude of 5 x 1 amp flowing eastward at an altitude of 1 km. Model computations were performed with the Rice IBM 37/155 computer. The variations of the vector components as well as the directions of the magnetic fields due to the following three cases, such as the electrojet, the sheet currents and the combination of the two along a path of rocket flight were individually included in details. For the electrojet current which was a kinked line current at the center, we get more details from a comparison with a straight line current in Chapter 2.en_US
dc.format.digitalOriginreformatted digitalen_US
dc.format.extent83 ppen_US
dc.identifier.callnoThesis Sp. Sci. 1974 Tengen_US
dc.identifier.citationTeng, Yuan-Cheng. "Magnetic perturbations due to current structural variations." (1974) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/103876">https://hdl.handle.net/1911/103876</a>.en_US
dc.identifier.digitalRICE1502en_US
dc.identifier.urihttps://hdl.handle.net/1911/103876en_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.titleMagnetic perturbations due to current structural variationsen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentSpace Scienceen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelMastersen_US
thesis.degree.nameMaster of Scienceen_US
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