Many authors have considered a gravitational origin of the magnetic field of celestial bodies. Especially, the so-called Wilson-Blackett formula has been investigated, both theoretically and observationally. It appeared possible to deduce this formula from general relativity, e. g., by application of a special interpretation of gravito-magnetic theory. More consequences of the latter theory for pulsars will be considered in this work. As an example, the standard quadrupolar charge density for pulsars can be deduced from the gravito-magnetic theory. Moreover, a new magnetic dipole moment from electromagnetic origin is found, generated in the basic magnetic field from gravito-magnetic origin. In general, for thirteen accreting, slowly rotating, binary pulsars the agreement between the observed magnetic field and the gravito-magnetic prediction is better than between the observed value and the value from the standard magnetic dipole radiation model. At present, an analogous comparison for five isolated pulsars appears to be difficult. For a sample of 100 pulsars the averaged (gravito-)magnetic field, extracted from the magnetic dipole spin-down model, is in fair agreement with the gravito-magnetic prediction. Unfortunately, the (gravito-)magnetic field has not yet directly been measured. Finally, it is found that the first and second order braking indices only depend on the magnetic field from electromagnetic origin.

The magnetic field of pulsars and the gravito-magnetic theory

As a sequel to the absorber theory of radiation of Wheeler and Feynman,1 Braffort and Tzara2 postulated the existence of a universal random electromagnetic field at the absolute zero of temperature—the zero-point field.

Stochastic Electrodynamics an Overview

The predictions of a model of the magnetic field of rotating bodies are compared with the results of observations of the magnetic fields of the planets. Further observations of the Mars and the lumar magnetic fields are suggested.

The magnetic field of the planets.

The origin of stellar magnetic fields is still uncertain. For decades a fossil field mechanism has been postulated for white dwarfs, based on magnetic flux conservation of Ap or Bp stars. Later on, dynamo action in the common envelope of binary systems has been proposed as an origin of magnetic fields in white dwarfs. Recently, dynamo action in the convective region of isolated white dwarfs has been considered as an explanation.

In this work a gravitational origin for the magnetic fields of rotating massive bodies is reinvestigated. This approach has led to the so-called Wilson-Blackett law that predicts a dipolar magnetic field for all rotating electrically neutral bodies. A short review of the history of this law is given. The validity of the Wilson-Blackett formula for white dwarfs will be examined in this work.

Results are given for ten isolated white dwarfs, eleven AM Herculis systems, one DQ Herculis system and two double-white-dwarf binaries. In most cases only approximate agreement with the predictions of the Wilson- Blackett formula is found. Contributions from electromagnetic origin may be responsible for the deviations. The results for white dwarfs are compared with corresponding classes of pulsars.

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Magnetic White Dwarfs and Gravitomagnetism

The formulation of the magnetic field of rotating bodies, obtained within the framework of stochastic electrodynamics, and Hoyle's mechanism for the transfer of angular momentum are used in the proposed model of the origin of the solar system. The ensemble of numerical results obtained is in good agreement with observations.

The origin of the solar system and stochastic electrodynamics.

A laboratory experiment devoted to the measurement of the magnetic field created by a rotating body is described. Using an original method of detection, the effects of the magnetic field of a rotating body were detected and their properties investigated. Based on a model proposed by the author, an interpretation of the experimental results is given.

M. Surdin

Papers

Magnetic field of rotating bodies