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Kristian Birkeland

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Kristian Birkeland

Kristian Olaf Bernhard Birkeland (13 December 1867 - 15 June 1917) was a Norwegian scientist who has been called "the first space scientist"[1] and "the father of plasma experiments in the laboratory and space"[2] [3] [4]. He is perhaps most well-known for his scientific work on the aurora using a terrella (a magnetized globe), and as inventor of an electromagnetic cannon, and, a method of electrically producing artificial fertilizer. He also became a full professor of physics at the University of Oslo at the age of 31.

Birkeland also had astrophysical research published on cathode rays,[5] the Zodiacal lights,[6] comets,[7] the Sun and sunspots,[8] the origin of planets and their satellites,[9] the Earth's magnetism.[10]

Some of Birkeland's other contributions to science included:[2] • Derived the general expression for the Poynting vector • Gave the first general solution to Maxwell's equations [11] • Pioneered the field of charged-particle beams • Utilized the concept of "longitudinal mass" • Constructed the first foil diodes • Pioneered the field of visible-light photography of electrical discharges • Advocated charged-particle propulsion engines for space travel • Created Norsk Hydro's nitrogen-fertilizer industry (the Birkeland-Eyde method for production of potassium nitrate) • Invented an electromagnetic rail gun capable of firing a 10-kg projectile • Established Birkeland's Firearms company • Anticipated cosmic rays (discovered in 1911) with his calculations involving energies of several billion electron volts • Held patents on the electromagnetic cannon,[12] electric blankets, solid margarine, and hearing aids.

In 1969 when field-align currents had been identified in the Earth's atmosphere, they were named in his honor: Birkeland currents.[13]

Investigating the aurora

Birkeland's terrella showing a spiral form. Source: "On Possible Electric Phenomena in Solar Systems and Nebulae" (fig. 262)

After encouragement from his maths teacher encouraged, Birkeland bought a bar magnetic, and read about William Gilbert's (1544-1603) study of the Earth's magnetism, and his terrella made from naturally magnetized lodestone. Gilbert surmised that the Earth was like a bar magnet whose magnetism was somehow related to electricity.

He organized several expeditions to Norway's high-latitude regions where he established a network of observatories under the auroral regions to collect magnetic field data. The results of the Norwegian Polar Expedition conducted from 1899 to 1900 contained the first determination of the global pattern of electric currents in the polar region from ground magnetic field measurements. The discovery of X-rays inspired Birkeland to develop vacuum chambers to study the influence of magnets on cathode rays. An example of one of his experiments is depicted on the left front of the bank note. It shows a magnetized terrella, simulating the Earth, suspended in an evacuated box. Birkeland noticed that an electron beam directed toward the terrella was guided toward the magnetic poles and produced rings of light around the poles and concluded that the aurora could be produced in a similar way. He developed a theory in which energetic electrons were ejected from sunspots on the solar surface, directed to the Earth, and guided to the Earth's polar regions by the geomagnetic field where they produced the visible aurora. Birkeland was nominated for the Nobel Prize no less than seven times.

Electromagnetic cannon

Birkeland's electromagnetic railgun, from his patent application of 1902.[14]
See also: A. Egeland, "Birkeland's electromagnetic gun: a historical review", IEEE Transactions on Plasma Science, Apr 1989, Volume: 17, Issue: 2, page(s): 73-82, ISSN: 0093-3813. PEER REVIEWED

The scale of Birkeland's research enterprises was such that the time-honored matter of funding became an overwhelming obstacle. Recognizing that technological invention could bring wealth, he developed an electromagnetic cannon. In 1900, he obtained patents on what we now call an electromagnetic-coil-gun and, with some investors, formed a firearms company. The coil-gun worked, except the high muzzle velocities he predicted (600 m/s) were not produced. The most he could get from his largest machine was 100 m/s, corresponding to a disappointing projectile range of only 1 km. So he renamed the device an aerial torpedo and arranged a demonstration with the express aim of selling the company. At the demonstration, one of the coils shorted and produced a sensational inductive arc complete with noise, flame, and smoke. This was the first failure of any of the launchers that Birkeland had built. It could easily have been repaired and another demonstration organized. However, fate intervened in the form of an engineer named Sam Eyde.

At a dinner party only one week later, Eyde told Birkeland that there was an industrial need for the biggest flash of lightning that can be brought down to Earth in order to make artificial fertilizer. Birkeland's climactic reply was: I have it! There were no more attempts to sell the firearms company, and he worked with Eyde only long enough to build a plasma arc device for the nitrogen fixation process. The pair worked to develop the prototype furnace into a design that was economically viable for large-scale manufacture. Birkeland then enjoyed adequate funding for his only real interest: research.

The fact that Birkeland joined with Eyde as a business partner, appears to have been one of the reasons why Birkeland was unsuccessful in being awarded the Nobel Prize for his idea. Eyde wanted to be nominated along with Birkeland, however the Nobel Prize is designed to recognise the original idea, not any commercial applications. This resulted in a possibly contentious nomination, and this combined with the fact that at that time relations between Sweden and Norway were delicate, meant that he wasn't nominated by the committee.

Cosmic theories

In 1913, Birkeland may have been the first to predict that plasma was ubiquitous in space. He wrote: "It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. We have assumed that each stellar system in evolutions throws off electric corpuscles into space. It does not seem unreasonable therefore to think that the greater part of the material masses in the universe is found, not in the solar systems or nebulae, but in "empty" space. [15]

In 1916, Birkeland was probably the first person to successful predict that the solar wind behaves as do all charged particles in an electric field, "From a physical point of view it is most probable that these new solar rays are neither exclusively negative nor positive rays, but of both kinds"; in other words, the Solar Wind consists of both negative electrons and positive ions.[16]

Field-aligned "Birkeland" currents

Birkeland's terrella showing discharge-rays about the poles. Source: "On Possible Electric Phenomena in Solar Systems and Nebulae" (fig. 259)

Birkeland suggested that polar electric currents -- today referred to as auroral electrojets -- were connected to a system of currents that flowed along geomagnetic field lines into and away from the polar region. He provided a diagram of field-aligned currents in his book, "The Norwegian Aurora Polaris Expedition 1902-1903". This diagram is reproduced on the back of the bank note in the lower right corner. This book contains chapters on magnetic storms on the Earth and their relationship to the Sun, the origin of the Sun itself, comets, and the rings of Saturn. Birkeland's vision of field-aligned currents became the source of a controversy that continued for a quarter of a century, because their existence could not be confirmed from ground-based measurements alone.

The absolute proof of Birkeland's field-aligned currents could only come from observations made above the ionosphere with satellites. A magnetometer onboard a U.S. Navy navigation satellite launched in 1963 observed magnetic disturbances on nearly every pass over the high-latitude regions of the Earth.

The magnetic disturbances were originally interpreted as hydromagnetic waves, but it was soon realized that they were due to field-aligned or Birkeland currents. The first complete map of the statistical location of Birkeland currents in the Earth's polar region was developed in 1974 by A.J. Zmuda and J.C. Armstrong and refined in 1976 by T. Iijima and T.A. Potemra from satellite-borne magnetic field observations.

The ring encircling the magnetic pole depicted on the back of the bank note is similar to the patterns of Birkeland and current derived from satellites. Birkeland's face appears a second time in a watermark in the blank space above the drawing of the Terrella, and his rudimentary magnetosphere appears on the back but is only visible under ultraviolet light.

Personal life

Kristian Birkeland's portrait from a 200 Kroner bank note
200 Kroner bank note (front)

Kristian Birkeland was born on 13 December 1867 in Christiania (now called Oslo) in Norway, to Reinert Tønnesen Birkeland (1838–1899) and his wife Ingeborg Susanne Ege 1841-1913). He also had an older brother called Tønnes, [17] and one of his cousins, Richard Birkeland (1879–1928) became a professor of Applied Mathematics. His ancestors were farmers from a district called Birkeland in southern Norway.

Finishing school in 1885, Birkeland entered the University of Oslo studying chemistry and mathematics for two year, then switching to theoretical physics before graduating in 1890 with a Candidatus Realium degree. Two years later, he became a full-time research assistant, and was offered a scholarship, so he decide to travel abroad where he studied with French physicist Henri Poincaré, and Swiss physicists Lucien De La Rive, and Edouard Sarasin, investigating the energy transfer of electromagnetic waves.[4]

Kristian married fairly late in life (aged 37) to Ida Charlotte Hammer in May 1905. They had no children, and due to Kristian's work, their marriage eventually broke down, and in 1911, they divorced.[18]

Quotes

It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. — Kristian Birkeland
A very few lonely pioneers make their way to high places never before visited . . . they create the living conditions of mankind and the majority are living on their work. — Kristian Birkeland

Footnotes

  1. *Kristian Birkeland, The First Space Scientist (2005) [ISBN 1-4020-3293-5] by Egeland, Alv, Burke, William J. PEER REVIEWED (Contents)
  2. 2.0 2.1 A. L. Peratt; C.-G. Fälthammar, N. Rynn, "Guest Editorial: Plasma Experiments in the Laboratory and in Space" IEEE Transactions on Plasma Science Vol. 20 No.6 (Dec 1992) PEER REVIEWED (full text) FULL TEXT PDF
  3. Kristian Birkeland, The Norwegian Aurora Polaris Expedition 1902-1903, Publ. H. Aschehoug & Co. Section 1 publ. 1908, Section 2 publ. 1913. Online in full FULL TEXT
  4. 4.0 4.1 A. Egeland, E. Leer, "Professor Kr. Birkeland: His Life and Work", in IEEE Transactions on Plasma Science Vol 14 No. 6 Dec 1986, p. 666-677, ISSN: 0093-3813 PEER REVIEWED
  5. "Sur un spectre des rayons cathodiques" FULL TEXT (On a spectrum of the cathode rays;) (1896) Comptes rendus hebdomadaires des séance de I'Academie des sciences, T. 123, 492-495. PEER REVIEWED
  6. "Calcul des lignes d'intensités égales dans la lumière zodiacal" PEER REVIEWED (Calculation of the lines of equal intensities in the zodiacal light) (1914) Birkeland et Skolem, Comptes rendus hebdomadaires des séances de l'Académie des sciences, T. 159, 495-497. PEER REVIEWED
  7. The Norwegian Aurora Polaris Expedition 1902-1903 Part II, Chapter 5. Is It Possible To Explain Zodiacal Light, Comets' Tails, And Saturn's Ring By Means Of Corpuscular Rays? (1913) ACADEMIC BOOK Section 124. Comet Tails FULL TEXT
  8. "Le soleil et ses taches" FULL TEXT (The Sun and its spots). (1911) Comptes rendus hebdomadaires des séances de l'Académie des sciences, T. 153, 456-459. PEER REVIEWED
  9. "Sur l'origine de planètes et de leurs satellites" FULL TEXT (On the origin of planets and their satellites) (1912) Comptes rendus hebdomadaires des séances de l'Académie des sciences, T. 155, 892-895. PEER REVIEWED
  10. "Sur la conservation et l'origine du magnetisme terrestre" FULL TEXT (On the conservation and origin of terrestrial magnetism). Comptes rendus hebdomadaires des séances de I'Académie des sciences, T. 157, 275-277. PEER REVIEWED
  11. Kr. Birkeland, "Solution generale des equations de Maxwell pour un milieu absorbant homogene et isotrope" FULL TEXT Comptes Rendus (Paris), vol. CXXI, 1895. PEER REVIEWED
  12. US Patent number   754637 (1902) Electromagnetic Gun FULL TEXT
  13. * Schield, M. A.; Freeman, J. W.; Dessler, A. J., (1969) "A Source for Field-Aligned Currents at Auroral Latitudes", Journal of Geophysical Research, Vol. 74, p.247. PEER REVIEWED
  14. "Electromagnetic Gun", US Patent number 754637
  15. Kristian Birkeland, The Norwegian Aurora Polaris Expedition 1902-1903, Publ. H. Aschehoug & Co. Section 1 publ. 1908, Section 2 publ. 1913. Online in full FULL TEXT p.720
  16. Kristian Birkeland, "Are the Solar Corpuscular Rays that penetrate the Earth's Atmosphere Negative or Positive Rays?" Videnskapsselskapets Skrifter, I Mat -- Naturv. Klasse No.1, Christiania, 1916.
  17. Professor Alf Egeland, "Olav Christian Bernhard Birkeland", Web site, Research group for Plasma and Space Physics, University of Oslo
  18. Lucy Jago, The Northern Lights: The True Story of the Man Who Unlocked the Secrets of the Aurora Borealis (2001) [ISBN 0-375-40980-7]

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