Robert A. Helliwell (September 2, 1920 – May 3, 2011) was an

electrical engineer Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...

and professor at

Stanford University Stanford University, officially Leland Stanford Junior University, is a private research university in Stanford, California. The campus occupies , among the largest in the United States, and enrolls over 17,000 students. Stanford is consider ...

. He was one of the pioneering scientists in the study of

whistlers Whistler may refer to: * Someone who whistles Places Canada * Whistler, British Columbia, a resort town ** Whistler railway station ** Whistler Secondary School * Whistler Blackcomb, a ski resort in British Columbia * Whistler Mountain, British ...

and related

ionospheric The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an im ...

phenomena.

Early life

Helliwell was born in Red Wing,

Minnesota Minnesota () is a state in the upper midwestern region of the United States. It is the 12th largest U.S. state in area and the 22nd most populous, with over 5.75 million residents. Minnesota is home to western prairies, now given over to ...

, on September 2, 1920. He and his mother moved to Palo Alto,

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

after his father died. Helliwell and his wife, whom he knew in

high school A secondary school describes an institution that provides secondary education and also usually includes the building where this takes place. Some secondary schools provide both '' lower secondary education'' (ages 11 to 14) and ''upper seconda ...

, were both

undergraduates Undergraduate education is education conducted after secondary education and before postgraduate education. It typically includes all postsecondary programs up to the level of a bachelor's degree. For example, in the United States, an entry-lev ...

.Melissae Fellet, "Robert Helliwell, Radioscience and Magnetosphere Expert, Dead at 90," Stanford Report, May 20, 2011 at http://news.stanford.edu/news/2011/may/robert-helliwell-obit-052011.html

Career

Helliwell was associated with

for his entire career, receiving all his academic credentials there and becoming a member of the

electrical engineering Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...

faculty in 1946. Helliwell received his AB degree in 1942, a combined MA and electrical engineering degree in 1944, and his PhD in 1948.Electrical Engineering Prof. Helliwell Dies at 90, Stanford Daily News, May 24, 2011 at http://www.stanforddaily.com/2011/05/24/electrical-engineering-prof-helliwell-dies-at-90/

Whistlers

Helliwell's greatest discovery was accidental, as is often the case in science. Helliwell and one of his students, Jack Mallinckrodt, were investigating

lightning Lightning is a naturally occurring electrostatic discharge during which two electric charge, electrically charged regions, both in the atmosphere or with one on the land, ground, temporarily neutralize themselves, causing the instantaneous ...

noise Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arise ...

at very low radio frequencies at

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 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 Station Siple Station 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 (VLF) waves. Its location was selected to be near the Earth' ...

West Antarctica West Antarctica, or Lesser Antarctica, one of the two major regions of Antarctica, is the part of that continent that lies within the Western Hemisphere, and includes the Antarctic Peninsula. It is separated from East Antarctica by the Transant ...

, which was active from 1971 to 1988. Since the

wavelength In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, tro ...

of VLF radio signals is huge (a

frequency Frequency is the number of occurrences of a repeating event per unit of time. It is also occasionally referred to as ''temporal frequency'' for clarity, and is distinct from ''angular frequency''. Frequency is measured in hertz (Hz) which is eq ...

of 10 kHz corresponds to a wavelength of 30 kilometers, or 18.64 miles), the Siple Station had an

antenna Antenna ( antennas or antennae) may refer to: Science and engineering * Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves * Antennae Galaxies, the name of two collid ...

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 is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

. It was possible to inject these signals into the

magnetosphere In astronomy and planetary science, a magnetosphere is a region of space surrounding an astronomical object in which charged particles are affected by that object's magnetic field. It is created by a celestial body with an active interior dynam ...

, since the

ionosphere The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an ...

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 The 1989 Loma Prieta earthquake occurred on California's Central Coast on October 17 at local time. The shock was centered in The Forest of Nisene Marks State Park in Santa Cruz County, approximately northeast of Santa Cruz on a section of t ...

.A. C. Fraser-Smith, A. Bernardi, P. R. McGill, M. E. Ladd, R. A. Helliwell, and 0. G. Villard, Jr., "Low Frequency Magnetic Field Measurements Near the Epicenter of the M 7.1 Loma Prieta Earthquake," Geophysical Research Letters, vol. 17, no. 9 (August, 1990), pp. 1465-1468 at 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.R. Raghuram, T. F. Bell, R. A. Helliwell, and J. P. Katsufrakis, "A Quiet Band Produced by VLF Transmitter Signals in the Magnetosphere," Geophys. Res. Lett., vol. 4, no. 5 (May, 1977), pp. 199-202 at Another paper showed that the

alternating current Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to direct current (DC) which flows only in one direction. Alternating current is the form in whic ...

power grids An electrical grid is an interconnected network for electricity delivery from producers to consumers. Electrical grids vary in size and can cover whole countries or continents. It consists of:Kaplan, S. M. (2009). Smart Grid. Electrical Power ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

(60 Hz) and

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

(50 Hz) affect

auroral chorus An auroral chorus is a series of electromagnetic waves at frequencies which resemble chirps, whistles, and quasi-musical sounds in predominantly rising tones when played as pressure waves (sound), which are created by geomagnetic storms also respo ...

emissions.J. Luette, C. Park, and R. Helliwell, The Control of the Magnetosphere by Power Line Radiation, J. Geophys. Res., vol. 84, no. A6 (June, 1979), pp. 2657-2660 at http://nova.stanford.edu/~vlf/publications/220.pdf

Honors

Helliwell was a

fellow A fellow is a concept whose exact meaning depends on context. In learned or professional societies, it refers to a privileged member who is specially elected in recognition of their work and achievements. Within the context of higher education ...

of the

Institute of Electrical and Electronics Engineers The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operation ...

and the

American Geophysical Union The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, atmospheric, ocean, hydrologic, space, and planetary scientists and enthusiasts that according to their website includes 130,000 people (not members). AGU's act ...

, and a member of the

American Association for the Advancement of Science The American Association for the Advancement of Science (AAAS) is an American international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific respons ...

and the

United States National Academy of Sciences The National Academy of Sciences (NAS) is a United States nonprofit, non-governmental organization. NAS is part of the National Academies of Sciences, Engineering, and Medicine, along with the National Academy of Engineering (NAE) and the Nati ...

.Robert A. Helliwell, Professor Emeritus of Electrical Engineering, Stanford Personal Web Site at The

National Science Foundation The National Science Foundation (NSF) is an independent agency of the United States government that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National I ...

named a range of hills in Antarctica, along the coast of

Victoria Land Victoria Land is a region in eastern Antarctica which fronts the western side of the Ross Sea and the Ross Ice Shelf, extending southward from about 70°30'S to 78°00'S, and westward from the Ross Sea to the edge of the Antarctic Plateau. It ...

on the Ross Sea, the

Helliwell Hills The Usarp Mountains are a major Antarctic mountain range, lying west of the Rennick Glacier and trending north to south for about . The feature is bounded to the north by Pryor Glacier and the Wilson Hills. These mountains were discovered an ...

in his honor.Listening in on lightning, Stanford Engineering Web Site at

References

External links

Very Low Frequency Group
webpage

{{DEFAULTSORT:Helliwell, Robert Stanford University School of Engineering faculty 1920 births 2011 deaths Members of the United States National Academy of Sciences American electrical engineers Fellow Members of the IEEE Fellows of the American Geophysical Union