The velocities of HF-induced short scale striations

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dc.contributor.advisorGordon, William E.en_US
dc.contributor.committeeMemberChamberlain, Joseph W.en_US
dc.contributor.committeeMemberCloutier, Paul A.en_US
dc.creatorCoster, A. J. (Anthea J.)en_US
dc.date.accessioned2018-12-18T21:18:40Zen_US
dc.date.available2018-12-18T21:18:40Zen_US
dc.date.issued1981en_US
dc.description.abstractShort scale striations are among the phenomena that occur when the ionosphere is heated by high frequency (HF) radio waves with ordinary mode polarization. These striations are electron density irregularities aligned along the magnetic field lines in and near the heated region of the ionosphere. They are a direct consequence of the heating and disappear within seconds after the heater has been turned off. The striations are detected to be moving in the heated region. Experiments were performed in June 1977 to investigate short scale striations. The experiments combined the use of a portable 5 MHz radar located on the island of Guadeloupe with heating facilities at the Arecibo Observatory. The 5 MHz radar had a line of sight that was orthogonal to the magnetic field lines in the F region above Arecibo and was used to detect the striations and their velocities. The 43 MHz radar at Arecibo was used for additional diagnostics. Varying the power of the HF radio wave did not appear to affect the striation velocities. Instead, their velocities appeared to be well correlated with general F-region ionization drifts. On two evenings, shortly after ionospheric sunset, dramatic changes in the striation velocities were observed. These F-region velocity disturbances occur in conjunction with the intensification of existing sporadic-E regions. Only during these disturbed time periods were reflections from sporadic E detected at greater than 5 MHz. A mechanism whereby the sporadic-E regions cause the alternate coupling and decoupling of the E and F regions in the early evening hours is presented. This mechanism can explain changes in local F-region electric fields which would cause the velocity disturbances.en_US
dc.format.digitalOriginreformatted digitalen_US
dc.format.extent65 ppen_US
dc.identifier.callnoThesis Sp. Sci. 1981 Costeren_US
dc.identifier.citationCoster, A. J. (Anthea J.). "The velocities of HF-induced short scale striations." (1981) Master’s Thesis, Rice University. <a href="https://hdl.handle.net/1911/104196">https://hdl.handle.net/1911/104196</a>.en_US
dc.identifier.digitalRICE1823en_US
dc.identifier.urihttps://hdl.handle.net/1911/104196en_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.titleThe velocities of HF-induced short scale striationsen_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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