• Login
    View Item 
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Older Theses Not Clearly Affiliated with a Current College
    • View Item
    •   Home
    • University of Alaska Fairbanks
    • UAF Graduate School
    • Older Theses Not Clearly Affiliated with a Current College
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Browse

    All of Scholarworks@UACommunitiesPublication DateAuthorsTitlesSubjectsTypeThis CollectionPublication DateAuthorsTitlesSubjectsType

    My Account

    Login

    First Time Submitters, Register Here

    Register

    Statistics

    Display statistics

    Time-dependent electron transport and optical emissions in the aurora

    • CSV
    • RefMan
    • EndNote
    • BibTex
    • RefWorks
    Thumbnail
    Name:
    Peticolas_L_2000.pdf
    Size:
    4.356Mb
    Format:
    PDF
    Download
    Author
    Peticolas, Laura Marie
    Chair
    Lummerzheim, Dirk
    Keyword
    Optics
    Electromagnetics
    Metadata
    Show full item record
    URI
    http://hdl.handle.net/11122/9542
    Abstract
    This thesis presents the first time-dependent transport model of auroral electrons. The evolution of the spherical electron intensity in phase space is studied for a variety of incident electron intensities. It is shown that the secondary electrons with energies <10 eV and at altitudes >150 km can take over 300 ms to reach steady state in phase space. Since there are bright optical emissions in this region, such a time dependence in the auroral electrons is important. The emissions of N2(2PG) 3371 A and <math> <f> <rm>N<sup>+</sup><inf>2</inf></rm></f> </math> (1NG) 4278 A are studied for time-varying electron pulses to show for the first time that this ratio will change until the secondary electrons reach steady state in the ionosphere. The way in which the 3371A/4278A ratio changes with time-varying precipitation depends on the precipitating electron spectra. The changes in the emission ratio can be used to learn more about the auroral acceleration region and the role of the ionosphere in auroral emissions. Field-aligned bursts (FABs), often observed in electron spectra of instruments flying over flickering aurora, are modeled with the time-dependent transport model. How the ionosphere modifies these electrons is shown. The 3371 and 4278 A emissions of flickering FABs are modeled to study the optical effects of modulated electron intensities in time. A study of 4278 A emissions for electron source regions from 630 to 4,000 km are studied along with frequency variations from 5 to 100 Hz. This study shows that the percent variation of the maximum to the minimum column brightness is less for higher frequencies and more distant source regions. It is shown that with an accurate time-dependent transport calculation and 4278 A emission observations of flickering aurora it should be possible to deduce the source altitude of the modulated electrons creating the optical flickering.
    Description
    Dissertation (Ph.D.) University of Alaska Fairbanks, 2000
    Date
    2000
    Type
    Dissertation
    Collections
    Older Theses Not Clearly Affiliated with a Current College
    Theses (Unassigned)

    entitlement

     
    ABOUT US|HELP|BROWSE|ADVANCED SEARCH

    The University of Alaska Fairbanks is an affirmative action/equal opportunity employer and educational institution and is a part of the University of Alaska system.

    ©UAF 2013 - 2023 | Questions? ua-scholarworks@alaska.edu | Last modified: September 25, 2019

    Open Repository is a service operated by 
    Atmire NV
     

    Export search results

    The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

    By default, clicking on the export buttons will result in a download of the allowed maximum amount of items.

    To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

    After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.