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Louis Miles Muggleton, FIET (8 July 1922 – 5 April 2015) was a South African-born British Ionospheric
Physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...
and
Electrical Engineer Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems that use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...
. Building on the work of Sir Edward Appleton in 1975 Muggleton's seminal work provided the international standard
ITU The International Telecommunication Union (ITU)In the other common languages of the ITU: * * is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established ...
model of
radio wave Radio waves (formerly called Hertzian waves) are a type of electromagnetic radiation with the lowest frequencies and the longest wavelengths in the electromagnetic spectrum, typically with frequencies below 300 gigahertz (GHz) and wavelengths g ...
absorption Absorption may refer to: Chemistry and biology *Absorption (biology), digestion **Absorption (small intestine) *Absorption (chemistry), diffusion of particles of gas or liquid into liquid or solid materials *Absorption (skin), a route by which su ...
and
reflection Reflection or reflexion may refer to: Science and technology * Reflection (physics), a common wave phenomenon ** Specular reflection, mirror-like reflection of waves from a surface *** Mirror image, a reflection in a mirror or in water ** Diffuse r ...
of the Heaviside layer (or E-layer) of 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 ...
. This model was based on jointly published work with Stamatis Kouris from the early 1970s.


Biography

Louis Muggleton was born in
Sterkstroom Sterkstroom is a settlement in Enoch Mgijima Local Municipality of the Chris Hani District in the Eastern Cape province of South Africa. The village is on the Hex River, at the southern foot of the Stormberg, 272 km north-west of East Lon ...
,
South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...
, the son of Oscar Muggleton and Ethel Helen Eliza Verran. Educated at Umtali High School in
Southern Rhodesia Southern Rhodesia was a self-governing British Crown colony in Southern Africa, established in 1923 and consisting of British South Africa Company (BSAC) territories lying south of the Zambezi River. The region was informally known as South ...
, in 1940 he was awarded a Beit Engineering Scholarship to the
University of Cape Town The University of Cape Town (UCT) (, ) is a public university, public research university in Cape Town, South Africa. Established in 1829 as the South African College, it was granted full university status in 1918, making it the oldest univer ...
where he graduated with a first class BSc degree in 1948. This was followed by a PhD in Antenna Design in 1960. During the
Second World War World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...
he joined the
British Army The British Army is the principal Army, land warfare force of the United Kingdom. the British Army comprises 73,847 regular full-time personnel, 4,127 Brigade of Gurkhas, Gurkhas, 25,742 Army Reserve (United Kingdom), volunteer reserve perso ...
, travelled to England, and transferred to the
Royal Corps of Signals The Royal Corps of Signals (often simply known as the Royal Signals – abbreviated to R SIGNALS) is one of the combat support arms of the British Army. Signals units are among the first into action, providing the battlefield communications an ...
. Within a year he was promoted to
lieutenant A lieutenant ( , ; abbreviated Lt., Lt, LT, Lieut and similar) is a Junior officer, junior commissioned officer rank in the armed forces of many nations, as well as fire services, emergency medical services, Security agency, security services ...
, in charge of a platoon. Trained to be involved in the
D-Day landings The Normandy landings were the landing operations and associated airborne operations on 6 June 1944 of the Allied invasion of Normandy in Operation Overlord during the Second World War. Codenamed Operation Neptune and often referred to as ...
, in 1944 he was posted to
India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
for the remainder of the war. After the war, Muggleton returned to
Southern Rhodesia Southern Rhodesia was a self-governing British Crown colony in Southern Africa, established in 1923 and consisting of British South Africa Company (BSAC) territories lying south of the Zambezi River. The region was informally known as South ...
where he was placed in charge of founding the Post Office Engineering College in 1950. In 1961, following an interchange of letters with Sir Edward Appleton, he was invited to take up a position on the staff of the Department of Electrical Engineering at the
University of Edinburgh The University of Edinburgh (, ; abbreviated as ''Edin.'' in Post-nominal letters, post-nominals) is a Public university, public research university based in Edinburgh, Scotland. Founded by the City of Edinburgh Council, town council under th ...
(1961-1973). At this time he began to provide technical assistance in
short wave Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (app ...
frequency selection and antenna design for
Trans World Radio Trans World Radio (TWR) is a multi-national evangelical Christianity, Christian media distributor. The largest Christian media organization in the world, it uses high-powered medium wave (AM) and short wave transmitters, local FM radio stations ...
. In 1973 he returned to Africa to found the Faculty of Engineering at the
University of Rhodesia The University of Zimbabwe (UZ) is a public university in Harare, Zimbabwe. It was opened in 1952 as the University College of Rhodesia and Nyasaland, and was initially affiliated with the University of London. It was later renamed the Univers ...
, as a Professor and Dean of Faculty. Following serious injuries in a campus-based terrorist attack, he moved back to the UK in 1980, taking up a position as Director of the British Branch of
Trans World Radio Trans World Radio (TWR) is a multi-national evangelical Christianity, Christian media distributor. The largest Christian media organization in the world, it uses high-powered medium wave (AM) and short wave transmitters, local FM radio stations ...
and overall Director of the
Propagation Propagation can refer to: *Chain propagation in a chemical reaction mechanism *Crack propagation, the growth of a crack during the fracture of materials *Propaganda, non-objective information used to further an agenda *Reproduction, and other forms ...
Department. Muggleton retired to take up an honorary position at the
University of Exeter The University of Exeter is a research university in the West Country of England, with its main campus in Exeter, Devon. Its predecessor institutions, St Luke's College, Exeter School of Science, Exeter School of Art, and the Camborne School of ...
in 1992. He died in 2015 and was survived by his wife Sylvia (m. 1947) and sons John, Robert, Andrew and
Stephen Stephen or Steven is an English given name, first name. It is particularly significant to Christianity, Christians, as it belonged to Saint Stephen ( ), an early disciple and deacon who, according to the Book of Acts, was stoned to death; he is w ...
.


Work

At the age of 20, interrupting a lecture during his signals training, Muggleton corrected an assertion about limits of the reflective nature of the ionosphere. He was asked to prove his claim to a group of British Army generals and succeeded in demonstrating Appleton's theoretical prediction that radio signals could be reflected from the Heaviside layer of the ionosphere even when transmitted vertically. His demonstration went on to be significant in its use for troop communications between the fjords in the Allied liberation of
Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...
during the winter of 1944-1945. In work published in 1968 and 1969 Muggleton studied long-term oscillatory variations in the relationship between F-region
ionization Ionization or ionisation is the process by which an atom or a molecule acquires a negative or positive Electric charge, charge by gaining or losing electrons, often in conjunction with other chemical changes. The resulting electrically charged at ...
and visible
solar activity Solar phenomena are natural phenomena which occur within the Stellar atmosphere, atmosphere of the Sun. They take many forms, including solar wind, Solar radio emission, radio wave flux, solar flares, coronal mass ejections, Stellar corona#Coron ...
. In these studies he showed that a dominant component was a
cosine In mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side opposite that ...
term of period equal to four sunspot cycles. The last crossing of the zero line was shown to have occurred during the 1947–1948
sunspot Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are one of the most recognizable Solar phenomena and despite the fact that they are mostly visible in the solar photosphere they usually aff ...
maximum, making that epoch of importance to statistical methods designed to remove this secular variation from ionospheric studies. In an extension of this work in 1971 Muggleton showed that the
regression coefficients In statistics, linear regression is a model that estimates the relationship between a scalar response (dependent variable) and one or more explanatory variables (regressor or independent variable). A model with exactly one explanatory variable i ...
between E-region peak
electron density Electron density or electronic density is the measure of the probability of an electron being present at an infinitesimal element of space surrounding any given point. It is a scalar quantity depending upon three spatial variables and is typical ...
, N_m(E), and
sunspot Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area. They are one of the most recognizable Solar phenomena and despite the fact that they are mostly visible in the solar photosphere they usually aff ...
number, R, depend on the particular
solar cycle The Solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a periodic 11-year change in the Sun's activity measured in terms of Modern Maximum, variations in the number of observed sunspots on the Sun ...
investigated. He found that a representative worldwide relationship for the 1949–1959
solar cycle The Solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a periodic 11-year change in the Sun's activity measured in terms of Modern Maximum, variations in the number of observed sunspots on the Sun ...
, is given, by N_M(E) = k_1(f_0 E)^2 = k_2(1+0.00334R) where f_0 E is the
critical frequency Critical or Critically may refer to: *Critical, or critical but stable, medical states **Critical, or intensive care medicine *Critical juncture, a discontinuous change studied in the social sciences. *Critical Software, a company specializing in ...
of the Heaviside layer and k_1,k_2 are constants. In 1973 using f_0 E and data from a period of 11 years, from 45 ionospheric stations, Muggleton and Kouris, his PhD student, investigated the value of the diurnal exponent p in the expression (f_0 E)^4 = A(cos \chi)^p where \chi is the
solar zenith angle The solar zenith angle is the zenith angle of the sun, i.e., the angle between the sun’s rays and the vertical direction. It is the complement to the solar altitude or solar elevation, which is the altitude angle or elevation angle between the ...
and p is the diurnal exponent. They found that firstly the value of p does not vary with season and that secondly it does not exhibit any systematic variation with the latitude of the station. In a related article in 1973 they investigated the world morphology of the Appleton E-layer seasonal anomaly and showed that it depends not only on
latitude In geography, latitude is a geographic coordinate system, geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at t ...
but also on
longitude Longitude (, ) is a geographic coordinate that specifies the east- west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek lett ...
and
hemisphere Hemisphere may refer to: In geometry * Hemisphere (geometry), a half of a sphere As half of Earth or any spherical astronomical object * A hemisphere of Earth ** Northern Hemisphere ** Southern Hemisphere ** Eastern Hemisphere ** Western Hemi ...
. They suggested that the anomaly could be the result of seasonal variations in the Sq current system. Later in 1974 together they went on to conduct a statistical investigation of the variation of E-region critical frequency f_0 E with
solar activity Solar phenomena are natural phenomena which occur within the Stellar atmosphere, atmosphere of the Sun. They take many forms, including solar wind, Solar radio emission, radio wave flux, solar flares, coronal mass ejections, Stellar corona#Coron ...
,
solar zenith angle The solar zenith angle is the zenith angle of the sun, i.e., the angle between the sun’s rays and the vertical direction. It is the complement to the solar altitude or solar elevation, which is the altitude angle or elevation angle between the ...
and season, to obtain a describing function of f_0 E in terms of
geographic latitude In geography, latitude is a geographic coordinate that specifies the north-south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from −90° at the south pole to 90° at the ...
,
solar zenith angle The solar zenith angle is the zenith angle of the sun, i.e., the angle between the sun’s rays and the vertical direction. It is the complement to the solar altitude or solar elevation, which is the altitude angle or elevation angle between the ...
and 10.7 cm solar radio-noise
flux Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications in physics. For transport phe ...
, for the design of ionospheric transmission paths. The reliability of the f_0 E expression was assessed by comparing predicted and observed values at various stations worldwide. In 1975 Muggleton's seminal work was accepted by the
ITU The International Telecommunication Union (ITU)In the other common languages of the ITU: * * is a specialized agency of the United Nations responsible for many matters related to information and communication technologies. It was established ...
in Geneva as the internationally accepted model of absorption and reflection of the E-layer.


Awards

* Fellow of the
Institution of Engineering and Technology The Institution of Engineering and Technology (IET) is a multidisciplinary professional engineering institution. The IET was formed in 2006 from two separate institutions: the Institution of Electrical Engineers (IEE), dating back to 1871,Engin ...
(1975)


See also

*
Sporadic E propagation Sporadic E (abbreviated E or SpE) is an uncommon form of radio propagation using a low level of the Earth's ionosphere that normally does not refract radio waves above about 15 MHz. Sporadic E propagation reflects signals off rel ...
*'' Journal of Atmospheric and Terrestrial Physics'', founded by Edward Appleton


References

{{DEFAULTSORT:Muggleton, Louis Miles 1922 births 2015 deaths Academics of the University of Edinburgh Academic staff of the University of Zimbabwe University of Cape Town alumni 20th-century South African physicists 20th-century British physicists British Army personnel of World War II Royal Corps of Signals officers South African emigrants to the United Kingdom South African expatriates in Southern Rhodesia