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Oleg D Jefimenko

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Oleg D. Jefimenko
Oleg D. Jefimenko
Born(1922-10-14)October 14, 1922
Kharkiv, Ukrainian SSR
DiedMay 14, 2009(2009-05-14) (aged 86)
Morgantown, West Virginia, United States
NationalityUkrainian / American
Alma materLewis and Clark College
University of Oregon
Known forJefimenko's equations, Electromagnetic Retardation, Gravitation and cogravitation
Scientific career
FieldsPhysics
InstitutionsWest Virginia University

Oleg Dmitrovich Jefimenko (October 14, 1922 – May 14, 2009) was a Ukrainian-American physicist and Professor Emeritus of Physics at West Virginia University. He is best known for Jefimenko's equations, which give the electric and magnetic fields due to a distribution of electric charges and electric current, taking into account the propagation delay (retardation) of the fields. He also worked extensively on the causal interpretation of electromagnetism and on generalizing Newton's theory of gravitation to time-dependent systems.

Biography

Jefimenko was born on October 14, 1922, in Kharkiv, in the Ukrainian SSR. He emigrated to the United States in 1951 and spent the remainder of his career there. He died on May 14, 2009, in Morgantown, West Virginia.

Education

Jefimenko studied at the University of Göttingen in Germany, where he obtained a Vordiplom in 1950. After coming to the United States he earned a bachelor's degree from Lewis and Clark College in 1952, and a master's degree (1954) and Ph.D. (1956) from the University of Oregon.

Career

Jefimenko joined West Virginia University in Morgantown in 1956. He served as assistant professor from 1956 to 1961, associate professor from 1961 to 1966, and full professor of physics from 1966 onward, later becoming Professor Emeritus. His 1966 textbook, Electricity and Magnetism, which presents the equations now known as Jefimenko's equations, remained in print through several editions.

Scientific contributions

Jefimenko's equations describe the electric and magnetic fields produced by an arbitrary distribution of charge and current, expressed as retarded integrals that account for the finite speed at which electromagnetic influences propagate. They provide a solution of Maxwell's equations for given time-dependent sources and are used to illustrate the causal relationship between sources and fields.

A central theme of Jefimenko's later work was the theory of electromagnetic retardation and its relation to relativity. He argued that many relations customarily regarded as consequences of relativistic electrodynamics can be derived directly from Maxwellian electromagnetic theory and electromagnetic force relations through the theory of electromagnetic retardation.

Jefimenko also worked on generalizing Newton's gravitational theory to time-dependent systems. He developed the concept of a second gravitational field, the "cogravitational" (or Heaviside's) field, which is closely analogous to the gravitomagnetic field of general relativity and had first been proposed by Oliver Heaviside in his 1893 article "A Gravitational and Electromagnetic Analogy." In this framework the time-dependent gravitational and cogravitational fields are expressed as retarded integrals that reduce to the equations of Newton's theory for time-independent systems.

In experimental physics, Jefimenko constructed and operated electrostatic motors and generators driven by atmospheric electricity, and he studied electrets. He is credited with reviving and demonstrating designs such as the Franklin electric motor.

Honors

Jefimenko received the Sigma Xi Prize in 1956. He won awards in the American Association of Physics Teachers (AAPT) Apparatus Competition in 1971 and 1973.

Selected articles

  1. "Force Exerted on a Stationary Charge by a Moving Electric Current or by a Moving Magnet," American Journal of Physics, V61, p. 218-222 (1993).
  2. "Torque exerted by a moving electric charge distribution on a stationary electric charge distribution," J. Phys. A: Math. Gen. 32, 5305- 5314 (2002).
  3. "Dynamic electric field maps," The Physics Teacher, 38, 154-157 (2000).
  4. "On the relativistic invariance of Maxwell's equations," Z. Naturforsch. 54a 637-644 (1999).
  5. "The Trouton-Noble paradox," J. Phys. A: Math. Gen. 32, 3755- 3762 (1999).
  6. "A relativistic paradox seemingly violating conservation of momentum law in electromagnetic systems," Eur. J. Phys. 20, 39-44 (1999).
  7. "On the experimental proofs of relativistic length contraction and time dilation," Z. Naturforsch. 53a, 977-982 (1998).
  8. "On Maxwell's displacement current," Eur. J. Phys. 19, 469-470 (1998).
  9. "Correct use of Lorentz-Einstein transformation equations for electromagnetic fields," Eur. J. Phys. 18, 444-447 (1997).
  10. "Is magnetic field due to an electric current a relativistic effect?" Eur. J. Phys. 17, 180-182 (1996).
  11. "Retardation and relativity: new integrals for electric and magnetic potentials of time-independent charge distributions moving with constant velocity," Eur. J. Phys. 17, 258-264 (1996).
  12. "Direct calculation of time dilation," Am. J. Phys. 64, 812-814 (1996).
  13. "Derivation of relativistic force transformation equations from Lorentz force law," Am J. Phys. 64, 618-620 (1996).
  14. "The nature of electromagnetic induction," Galilean Electrodynamics 6, 83-86 (1995).
  15. "Retardation and relativity: Derivation of Lorentz-Einstein transformations from retarded integrals for electric and magnetic fields," Am. J. Phys. 63, 267-272 (1995).
  16. "Retardation and relativity: The case of a moving line charge," Am. J. Phys. 63, 454-459 (1995).
  17. "Derivation of relativistic transformations for gravitational fields from retarded integrals," Galilean Electrodynamics 6, 23-30 (1995).
  18. "Gravitational field of a point mass moving with uniform linear or circular velocity," Galilean Electrodynamics 5, 25-33 (1994).
  19. "Direct calculation of the electric and magnetic fields of an electric point charge moving with constant velocity," Am. J. Phys. 62, 79-85 (1994).
  20. "Force exerted on a stationary charge by a moving electric current or by a moving magnet," Am. J. Phys. 61, 79-85 (1993).
  21. "Solutions of Maxwell's equations for electric and magnetic fields in arbitrary media," Am. J. Phys. 60, 899-902 (1992).
  22. "Direct calculation of electric and magnetic forces from potentials," Am. J. Phys. 58, 625-631 (1990).
  23. "Correct use of Maxwell stress equations for electric and magnetic fields," Am. J. Phys. 51, 988-996 (1983).
  24. "New method for calculating electric and magnetic fields and forces," Am J. Phys. 51, 545-551 (1983).
  25. "Electrets," (with D. K. Walker) Phys. Teach. 18, 651-659 (1980).
  26. "Water stream loop-the-loop," Am. J. Phys. 42, 103-106 (1974).
  27. "Volume charge in carnauba wax electrets," (with D. K. Walker) J. Appl. Phys. 44, 3459-3464 (1973).
  28. "Franklin electric motor," Am. J. Phys. 39, 1139-1141 (1971).
  29. "Operation of electric motors from atmospheric electric field," Am. J. Phys. 39, 776-779 (1971).
  30. "Electrostatic motors," (with D. K. Walker) Phys. Teach. 9, 121-129 (1971).
  31. "Semiclassical model of atomic interactions," J. Chem. Phys. 37, 2123-2126 (1962).
  32. "Demonstration of the electric fields of current-carrying conductors," Am. J. Phys. 30, 19-21 (1962).
  33. "Effect of the earth's magnetic field on the motion of an artificial satellite," Am. J. Phys. 27, 344-348 (1959).

Abstracts

Books

External links

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