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Tilghman (B. Noah) Photographs and Other Materials Documenting Antarctica
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  • Scope and Contents
  • Access to Collection
  • Publication Rights
  • Biographical / Historical
  • Preferred Citation

  • Language of Material: English
    Contributing Institution: Department of Special Collections and University Archives
    Title: B. Noah Tilghman photographs and other materials documenting Antarctica
    creator: Tilghman, B. Noah
    source: Tilghman, B. Noah
    Identifier/Call Number: SC1056
    Physical Description: 2.19 gigabyte(s)
    Physical Description: 1.5 Linear Feet
    Date (inclusive): 1972-1974
    Abstract: The materials consist of approximately 1000 color transparencies taken by B. Noah Tilghman documenting various United States and New Zealand resaerch bases in Antarctica, including the construction of Siple Station, as well as general living conditions, individuals, and landscapes.

    Scope and Contents

    The materials consist of approximately 1000 color slide transparencies taken by B. Noah Tilghman documenting various United States and New Zealand research bases in Antarctica, including the construction of Siple Station, as well as general living conditions, individuals, and landscapes.
    Each slide has a unique code, which matches a photo log (photocopy) included in the collection. As each roll of film was being mailed for development, each roll was numbered. This is the last number in the slide code. Austral summer 1972-1973 was designated "Ant", while the 1973-1974 season is represented by the "K" in the center of the code. Each frame of the roll was numbered at the beginning of the notation.
    The photo log gives photographic information as well as date, location and subject. Some of this information has also been written onto the individual slide frames. Abbreviations used include "EE" (electric eye) and "MPF" (maximum polarizing filter).

    Access to Collection

    The materials are open for research use.

    Publication Rights

    Copyright is retained by the creator of this collection for materials they have authored or otherwise produced. After the lifetime of the creator or on January 17, 2050, whichever occurs first, all intellectual property rights shall be transferred to and vest in Stanford. Copyright status for other collection materials is unknown. Transmission or reproduction of materials protected by U.S. Copyright Law (Title 17, U.S.C.) beyond that allowed by fair use requires the written permission of the copyright owners. Works not in the public domain cannot be commercially exploited without permission of the copyright owners. Responsibility for any use rests exclusively with the user.

    Biographical / Historical

    The Siple experiment was a Stanford, NSF funded, VLF- triggered emission experiment that took place from 1973 to 1988. Siple Station was established to perform experiments that actively probed the magnetosphere using very low frequency (VLF) waves. The Station included a 21.2 km dipole antenna located in Antarctica at 75.93 S, 84.25 W. Its location was selected because of various characteristics:
    1. The 2 km thick ice sheet at Siple allowed the construction of an antenna with a relatively high efficiency. With a 100 kW source, the antenna could obtain radiated powers on the order of 1 kW, which was necessary for stimulating wave-particle interactions in the magnetosphere.
    2. Siple's magnetic conjugate point was easily accessible, near the city of Roberval (also in Lake Mistassini), Quebec.
    3. Siple, at L = 4.3, was close to the plasmapause, where wave-particle resonances were likely to occur at the transmitted frequencies.
    4. Siple could be operated year-round [1].
    5. The station was effectively isolated from major EM noise in the VLF spectrum.
    The objective of the Siple transmitter was to produce various formats, which allowed for controlled experiments to answer specific questions regarding triggered emissions. The observed data after transmission included many unexplained phenomena. Some of the more obvious phenomena includes (but definitely not limited to): rising and falling emissions, wave growth, entrainment, and multiple-hop echos.
    Between 1973 and 1978, Siple operated with a transmitter known as Zeus. The Zeus transmitter could operate at one frequency at a time at powers up to 100kW. In 1978, the transmitter was replaced by the Jupiter transmitter, which could operate at multiple frequencies simultaneously and 150kW. In 1986, a second dipole antenna was added to explore polarization effects [2]. The Siple experiment ceased operation after the Antarctic summer of 1988.
    Two receiving stations were operated during the Siple experiment. The first was located at Roberval, Quebec. The gradual northwesterly drift of Siple's conjugate point due to the secular variation of the geomagnetic field and the increasing interference from local power lines required the movement of the receiver to Lake Mistissini, Quebec during the later years of operation.
    1.R . A. Helliwell and J . P . Katsufrakis, Upper Atmosphere Research in Antarctica, Chapter 5, Controlled Wave-Particle Interaction Experiments, pp. 100-129, Number 29 in the Antarctic Research Series . American Geophysical Union, 1978.
    2. R . A. Helliwell, "Vlf wave stimulation experiments in the magnetosphere from Siple Station, Antarctica," Review of Geophysics, vol. 26, no. 3, pp. 551-578, August 1988.

    Preferred Citation

    [identification of item], B. Noah Tilghman Color Transparencies and Other Materials Documenting Antarctica (SC1056). Dept. of Special Collections and University Archives, Stanford University Libraries, Stanford, Calif.

    Subjects and Indexing Terms

    Research -- California -- Stanford University.
    Scientific research
    United States Antarctic Research Program
    Helliwell, Robert A.
    Katsufrakis, John
    Stanford University. STAR Lab
    Tilghman, B. Noah
    Tilghman, B. Noah