Arthur V. Phelps [and] Sanborn C. Brown. / "January 3, 1952." / Bibliography: p. 8. / Army Signal Corps Contract No. DA36-039 sc-100 Project No. 8-102B-0. Dept. of the Army Project No. 3-99-10-022.

Manfred A. Biondi Sanborn C .Brown. / "August 3, 1949." / Bibliography: p. 6. / Army Signal Corps Contract No. W36-039-sc-32037 Project No. 102B Dept. of the Army Project No. 3-99-10-022

Thesis (M.A.)--University of North Carolina at Wilmington, 2006. / Includes bibliographical references (leaves: 96-97)

During magnetically disturbed periods, the spatially and temporally structured electron precipitation in the auroral zone creates a significant population of thermal secondary ions. Acceleration mechanisms exist that are capable of energizing the thermal population to suprathermal energies (1 eV to 1 keV). Suprathermal ions escape into the magnetosphere and undergo "bounce" motion along magnetic field lines. These ions are bound to the magnetic flux tubes, which undergo ExB convective drift within the magnetosphere. Magnetospheric convection transports flux tubes of bouncing suprathermal ions through the auroral zone and the subauroral polarization stream (SAPS) regions. Precipitating suprathermal ions enhance ionospheric plasma density structure and constitute a possible source for the enhanced echo occurrence observed by ground-based radars in the SAPS region. Satellite energy spectrometer data often show multiple bands of suprathermal particles with enhanced number and energy flux, and with an energy increase with increasing latitude. The present work examines the hypothesis that these signatures are the result of thermal secondary ions that have been accelerated out of the auroral ionosphere over the short time scales characterizing bursts of intense auroral electron precipitation. The analysis of three events of energy-dispersed ion signatures was facilitated by three-dimensional ion tracing software developed for this thesis. The short-lived acceleration hypothesis can account for the energy-dispersed ion signatures if there exist inter-hemispheric field aligned potentials of the order of 100 V. If the source of the ions is within the auroral zone, the suprathermal ions observed in the SAPS region are most likely to be O+ ions. The long bounce period of O+ (compared to H+) allows convection to transport O+ auroral ions equatorward through a convection reversal, into the SAPS region during a single half-bounce.

pas de résumé

During magnetically disturbed periods, the spatially and temporally structured electron precipitation in the auroral zone creates a significant population of thermal secondary ions. Acceleration mechanisms exist that are capable of energizing the thermal population to suprathermal energies (1 eV to 1 keV). Suprathermal ions escape into the magnetosphere and undergo "bounce" motion along magnetic field lines. These ions are bound to the magnetic flux tubes, which undergo ExB convective drift within the magnetosphere. Magnetospheric convection transports flux tubes of bouncing suprathermal ions through the auroral zone and the subauroral polarization stream (SAPS) regions. Precipitating suprathermal ions enhance ionospheric plasma density structure and constitute a possible source for the enhanced echo occurrence observed by ground-based radars in the SAPS region. Satellite energy spectrometer data often show multiple bands of suprathermal particles with enhanced number and energy flux, and with an energy increase with increasing latitude. The present work examines the hypothesis that these signatures are the result of thermal secondary ions that have been accelerated out of the auroral ionosphere over the short time scales characterizing bursts of intense auroral electron precipitation. The analysis of three events of energy-dispersed ion signatures was facilitated by three-dimensional ion tracing software developed for this thesis. The short-lived acceleration hypothesis can account for the energy-dispersed ion signatures if there exist inter-hemispheric field aligned potentials of the order of 100 V. If the source of the ions is within the auroral zone, the suprathermal ions observed in the SAPS region are most likely to be O+ ions. The long bounce period of O+ (compared to H+) allows convection to transport O+ auroral ions equatorward through a convection reversal, into the SAPS region during a single half-bounce.

No description available.

Thèse de doctorat : Sciences et techniques : Metz : 1999. / 1999METZ044S. 113 ref.

Thèse doctorat : Dispositifs de l'Electronique Intégrée : Villeurbanne, INSA : 2004. / Titre provenant de l'écran-titre. Bibliogr. à la fin de chaque chapitre.

Reproduction de : Thèse de doctorat : Physique des particules : Lyon 1 : 2005. / Titre provenant de l'écran titre. 92 réf. bibliographiques.