Robert Helliwell
Encyclopedia
Robert A. Helliwell was an electrical engineer and professor at Stanford University
. He was one of the pioneering scientists in the study of whistlers
and related ionospheric
phenomena.
, Minnesota
, on September 2, 1920. He and his mother moved to Palo Alto, California
after his father died. Helliwell and his wife, whom he knew in high school
, were both undergraduates at Stanford University
.[1]
for his entire career, receiving all his academic credentials there and becoming a member of the electrical engineering
faculty in 1946. Helliwell received his AB degree in 1942, a combined MA and electrical engineering degree in 1944, and his PhD in 1948.
noise
at very low radio frequencies at Stanford University
in 1950. Mallinckrodt heard some whistling sounds and brought them to Helliwell's attention. As Helliwell recalled in an article in the October, 1982, issue of the Stanford Engineer, he thought it was an artifact
, but he he stood radio watch with Mallinckrodt until he heard these whistlers for himself. Helliwell described these sounds as "weird, strange and unbelievable as flying saucers" in a 1954 article in the Palo Alto Times.
in West Antarctica
, which was active from 1971-1988. Since the wavelength
of VLF radio signals is huge (a frequency
of 10 kHz corresponds to a wavelength of 30 kilometers, or 18.64 miles), the Siple Station had an antenna
that was thirteen miles long. The antenna was used to transmit VLF radio signals into Earth's magnetosphere, to be detected half a world away in Canada
. It was possible to inject these signals into the magnetosphere
, since the ionosphere
is transparent to these low frequencies.
power grids in North America
(60 Hz) and Europe
(50 Hz) affect auroral chorus
emissions.
of the Institute of Electrical and Electronics Engineers
and the American Geophysical Union
, and a member of the American Association for the Advancement of Science
and the United States National Academy of Sciences
. The National Science Foundation
named a range of hills in Antarctica, along the coast of Victoria Land
on the Ross Sea
, the Helliwell Hills in his honor.
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
. He was one of the pioneering scientists in the study of whistlers
Whistler (radio)
A whistler is a very low frequency electromagnetic wave which can be generated, for example, by lightning. Frequencies of terrestrial whistlers are 1 to 30 kHz, with maximum usually at 3 to 5 kHz. Although they are electromagnetic waves, they occur at audio frequencies, and can be...
and related ionospheric
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
phenomena.
Early life
Helliwell was born in Red WingRed Wing, Minnesota
Red Wing is a city in Goodhue County, Minnesota, United States, on the Mississippi River. The population was 16,459 at the 2010 census. It is the county seat of Goodhue County....
, Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
, on September 2, 1920. He and his mother moved to Palo Alto, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
after his father died. Helliwell and his wife, whom he knew in high school
High school
High school is a term used in parts of the English speaking world to describe institutions which provide all or part of secondary education. The term is often incorporated into the name of such institutions....
, were both undergraduates at Stanford University
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
.[1]
Career
Helliwell was associated with Stanford UniversityStanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
for his entire career, receiving all his academic credentials there and becoming a member of the electrical engineering
Electrical engineering
Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...
faculty in 1946. Helliwell received his AB degree in 1942, a combined MA and electrical engineering degree in 1944, and his PhD in 1948.
Whistlers
Helliwell's greatest discovery was accidental, as is often the case in science. Helliwell and one of his students, John Mallinckrodt, were investigating lightningLightning
Lightning is an atmospheric electrostatic discharge accompanied by thunder, which typically occurs during thunderstorms, and sometimes during volcanic eruptions or dust storms...
noise
Noise
In common use, the word noise means any unwanted sound. In both analog and digital electronics, noise is random unwanted perturbation to a wanted signal; it is called noise as a generalisation of the acoustic noise heard when listening to a weak radio transmission with significant electrical noise...
at very low radio frequencies at Stanford University
Stanford University
The Leland Stanford Junior University, commonly referred to as Stanford University or Stanford, is a private research university on an campus located near Palo Alto, California. It is situated in the northwestern Santa Clara Valley on the San Francisco Peninsula, approximately northwest of San...
in 1950. Mallinckrodt heard some whistling sounds and brought them to Helliwell's attention. As Helliwell recalled in an article in the October, 1982, issue of the Stanford Engineer, he thought it was an artifact
Digital artifact
A digital artifact is any undesired alteration in data introduced in a digital process by an involved technique and/or technology.-Possible causes:...
, but he he stood radio watch with Mallinckrodt until he heard these whistlers for himself. Helliwell described these sounds as "weird, strange and unbelievable as flying saucers" in a 1954 article in the Palo Alto Times.
Research
In true scientific fashion, Helliwell tried to understand the mechanism involved in the production of whistlers. He conducted experiments at the VLF outpost, Siple StationSiple Station
Siple Station, Antarctica was a research station in Antarctica , established in 1973 by Stanford's STAR Lab, to perform experiments that actively probed the magnetosphere using very low frequency waves...
in West Antarctica
West Antarctica
West Antarctica, or Lesser Antarctica, one of the two major regions of Antarctica, is the part of the continent that lies within the Western Hemisphere including the Antarctic Peninsula.-Location and description:...
, which was active from 1971-1988. Since the wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
of VLF radio signals is huge (a frequency
Frequency
Frequency is the number of occurrences of a repeating event per unit time. It is also referred to as temporal frequency.The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency...
of 10 kHz corresponds to a wavelength of 30 kilometers, or 18.64 miles), the Siple Station had an antenna
Antenna
Antenna may refer to:-Science and engineering:* Antenna , also known as an aerial, a transducer designed to transmit or receive electromagnetic Antenna (pl. antennas in radio/TV, antennae in biology) may refer to:-Science and engineering:* Antenna (radio), also known as an aerial, a transducer...
that was thirteen miles long. The antenna was used to transmit VLF radio signals into Earth's magnetosphere, to be detected half a world away in Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
. It was possible to inject these signals into the magnetosphere
Magnetosphere
A magnetosphere is formed when a stream of charged particles, such as the solar wind, interacts with and is deflected by the intrinsic magnetic field of a planet or similar body. Earth is surrounded by a magnetosphere, as are the other planets with intrinsic magnetic fields: Mercury, Jupiter,...
, since the ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
is transparent to these low frequencies.
Writings
Helliwell was the author of one book, "Whistlers and Related Ionospheric Phenomena," and more than 90 scientific papers. Three of his papers deserve special mention. One of these reported on low frequency emissions associated with the 1989 Loma Prieta earthquake. Another describes how injection of a low frequency radio signal into the magnetosphere causes a radio quieting of the natural noise that's associated with these frequencies. Another paper showed that the alternating currentAlternating current
In alternating current the movement of electric charge periodically reverses direction. In direct current , the flow of electric charge is only in one direction....
power grids in North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
(60 Hz) and Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
(50 Hz) affect auroral chorus
Auroral chorus
An auroral chorus is a series of chirps, whistles, and quasi-musical sounds in predominantly rising tones created by geomagnetic storms also responsible for the auroras. The sounds last approximately 0.1-1.0 seconds...
emissions.
Honors
Helliwell was a fellowFellow
A fellow in the broadest sense is someone who is an equal or a comrade. The term fellow is also used to describe a person, particularly by those in the upper social classes. It is most often used in an academic context: a fellow is often part of an elite group of learned people who are awarded...
of the Institute of Electrical and Electronics Engineers
Institute of Electrical and Electronics Engineers
The Institute of Electrical and Electronics Engineers is a non-profit professional association headquartered in New York City that is dedicated to advancing technological innovation and excellence...
and the American Geophysical Union
American Geophysical Union
The American Geophysical Union is a nonprofit organization of geophysicists, consisting of over 50,000 members from over 135 countries. AGU's activities are focused on the organization and dissemination of scientific information in the interdisciplinary and international field of geophysics...
, and a member of the American Association for the Advancement of Science
American Association for the Advancement of Science
The American Association for the Advancement of Science is an international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsibility, and supporting scientific education and science outreach for the...
and the United States National Academy of Sciences
United States National Academy of Sciences
The National Academy of Sciences is a corporation in the United States whose members serve pro bono as "advisers to the nation on science, engineering, and medicine." As a national academy, new members of the organization are elected annually by current members, based on their distinguished and...
. The National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...
named a range of hills in Antarctica, along the coast of Victoria Land
Victoria Land
Victoria Land is a region of Antarctica bounded on the east by the Ross Ice Shelf and the Ross Sea and on the west by Oates Land and Wilkes Land. It was discovered by Captain James Clark Ross in January 1841 and named after the UK's Queen Victoria...
on the Ross Sea
Ross Sea
The Ross Sea is a deep bay of the Southern Ocean in Antarctica between Victoria Land and Marie Byrd Land.-Description:The Ross Sea was discovered by James Ross in 1841. In the west of the Ross Sea is Ross Island with the Mt. Erebus volcano, in the east Roosevelt Island. The southern part is covered...
, the Helliwell Hills in his honor.
Further reading
- Whistlers and Related Ionospheric Phenomena, Robert A. Helliwell, Stanford University Press, Stanford, California, 1965.