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Guide to the B. Noah Tilghman Color Transparencies and Other Materials Documenting Antarctica
SC1056
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Call Number: SC1056
Creator:
Tilghman, B. Noah
Title: B. Noah Tilghman color transparencies and other materials documenting Antarctica
Dates: 1972-1974
Physical Description:
1.5 Linear feet and 2.19 gigabytes
Summary: 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.
Language(s): The materials are in English.
Repository:
Dept. of Special Collections & University Archives.
Stanford University Libraries.
557 Escondido Mall
Stanford, CA 94305
Email: speccollref@stanford.edu
Phone: (650) 725-1022
URL: http://www-sul.stanford.edu/depts/spc/spc.html
The materials are open for research use.
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.
[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.
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.
References
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.
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).
Helliwell, Robert A., 1920-2011.
Katsufrakis, John
Stanford University. STAR Lab.
Tilghman, B. Noah
United States Antarctic Research Program.
Antarctica
Color transparencies
Electromagnetism
Research--California--Stanford University.
Scientific research