External Fields

  • Otto Nachtmann
Part of the Texts and Monographs in Physics book series (TMP)


Until now, we have treated only reactions taking place in the vacuum. In practice, however, one is often interested in processes which occur in the presence of a given electric or magnetic field. The external field may be produced by some macroscopic device such as a capacitor or an electromagnet, but it could equally well be the field due to an atomic nucleus. Some typical problems of this nature are the following:
  1. (i)

    The scattering of an electron by a given charge distribution, e.g., by a heavy nucleus whose recoil can be neglected.

  2. (ii)

    The emission of synchrotron radiation by an electron circulating in a storage ring.

  3. (iii)

    “Bremsstrahlung” radiation emitted by an electron as it is decelerated in the field of a nucleus. This process is used to produce X-rays in cathode-ray tubes.

  4. (iv)

    The production of an electron-positron pair by a photon in the field of a heavy nucleus. This process led to the discovery of the positron by Anderson in 1932. Today it serves as an experimental means of detecting photons in high energy physics.



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Copyright information

© Springer-Verlag Berlin Heidelberg 1990

Authors and Affiliations

  • Otto Nachtmann
    • 1
  1. 1.Institut für Theoretische PhysikUniversität HeidelbergHeidelbergFederal Republic of Germany

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