A. C. Fraser-Smith: Research Interests

[Note: Clicking on any one of the highlighted references below will give you a segment of Prof. Fraser-Smith's publication list with the desired reference usually at (or close to) the top of the segment.]

Prof. Fraser-Smith conducts experimental and theoretical research into the origin and properties of low frequency electromagnetic field variations in the Earth's environment and in space. The specific frequencies covered by this work are the following:

Prof. Fraser-Smith also investigates the relation of these ULF, ELF, and VLF electromagnetic variations to other phenomena on and below the Earth's surface (including the sea surface), in the neutral atmosphere, and in the ionosphere, magnetosphere, and interplanetary space.


This research included the first measurements of ULF geomagnetic field fluctuations with a superconducting magnetometer [Fraser-Smith and Buxton,1975 ] and it has led to a number of new discoveries:

Relevant current activities in this area of research are Prof. Fraser-Smith's involvement (with Emeritus Professors R. A. Helliwell and O. G. Villard, Jr.) in the following two projects:

(a) a project to measure the global distribution of ELF/VLF electromagnetic noise using a network of eight Stanford-designed (and constructed) measurement instruments. This project is sponsored primarily by the Office of Naval Research but it also receives logistics support from the National Science Foundation for the Arctic and Antarctic instrumentation and it has also received substantial support from the U.S. Air Force's Rome Laboratory.

(b) a project attempting to measure ULF magnetic signals prior to further earthquakes in California. Independent ULF measurements systems have been installed at the Varian and Haliburton ranches near Parkfield in Central California, where an earthquake with a magnitude greater than 6 is expected in the near future, and at Piñon Flat and Table Mountain in Southern California.
The above systems are all installed on or close to the San Andreas fault. When combined with the system originally installed at Corralitos, just south of the San Francisco Bay area, they enable ULF magnetic field fluctuations along a substantial section of the San Andreas fault to be monitored (see map of earthquake measurement sites). An additional two measurement systems have recently been installed along the Hayward Fault at Mission Peak and Lake Chabot on the east side of San Francisco Bay, and another will shortly be installed on the west side of San Francisco Bay in Stanford University's Jasper Ridge biological preserve, close to the segment of the San Andreas fault that gave us the great San Francisco earthquake of 1906 (and which has not moved since). The map of earthquake measurement sites shows the locations of all these measurement sites and their relation to the San Andreas fault. The measurement program is supported primarily by the U.S. Geological Survey; the recent Hayward fault installations were supported by EPRI and Stanford is supporting the Jasper Ridge installation.


Prof. Fraser-Smith has also been involved for some time in studies of the artificial generation of low-frequency electromagnetic waves, which can be used for active experiments in the Earth's upper atmosphere and for communication. One result of this work was the first use of a peninsula (on Chappaquiddick Island) as an antenna [Fraser-Smith and Villard,1980 ].

A relevant recent activity in this area of research was Prof. Fraser-Smith's involvement in a project, sponsored by the Rome Laboratory of the U.S. Air Force, to investigate the possible use of electron beams in space as low-frequency antennas. This work has led to an active involvement in electron beam experiments on the Space Shuttle and on rockets [e.g., Banks et al.,1990 Raitt et al.,1995].

Most recently, he participated in the two Tethered Satellite System (TSS) missions of the Space Shuttle and their associated electrodynamic tether system (SETS) experiments, since a 20--100 km long conducting tether in space could be a remarkably efficient antenna for the generation of low-frequency electromagnetic signals in space. See the home pages for Victor Aguero and Scott Williams.


In addition to the above activities, Prof. Fraser-Smith has the following related interests:


Finally, Prof. Fraser-Smith has long had an interest in the dipole models of the Earth's magnetic field and in the locations the north and south "geomagnetic" poles predicted by these models. He has published a definitive study of the eccentric dipole model of the Earth's magnetic field [Fraser-Smith,1987].

Remember that the references quoted can be found in Prof. Fraser-Smith's publication list.


[Return to the Fraser-Smith home page.]