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D Villarroel

Publications and source records attributed to D Villarroel.

4 recordsLinked to original sources
PubMed2002

Preacceleration in classical electrodynamics.

As is well known, the Lorentz-Dirac equation follows by means of a hypothesis of simplicity. When this hypothesis is ruled out, several additional terms can be added to the one that appears in the Lorentz-Dirac equation. We study the equation that considers the two terms explicitly shown by Dirac in his paper. It is shown, on general grounds, that the additional terms are not related to the radiation emitted by the electron; which is fully taken into account by the Larmor term of the Lorentz-Dirac equation. This result is explicitly verified by means of an exact solution of the enlarged Lorentz-Dirac equation that corresponds to a monoenergetic electron in circular orbit. Also it is shown that the additional term diminishes the effect of preacceleration in comparison with the one that comes from the Lorentz-Dirac equation.

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PubMed2002

Exact solutions to the Mo-Papas and Landau-Lifshitz equations.

Two exact solutions of the Mo-Papas and Landau-Lifshitz equations for a point charge in classical electrodynamics are presented here. Both equations admit as an exact solution the motion of a charge rotating with constant speed in a circular orbit. These equations also admit as an exact solution the motion of two identical charges rotating with constant speed at the opposite ends of a diameter. These exact solutions allow one to obtain, starting from the equation of motion, a definite formula for the rate of radiation. In both cases the rate of radiation can also be obtained, with independence of the equation of motion, from the well known fields of a point charge, that is, from the Maxwell equations. The rate of radiation obtained from the Mo-Papas equation in the one-charge case coincides with the rate of radiation that comes from the Maxwell equations; but in the two-charge case the results do not coincide. On the other hand, the rate of radiation obtained from the Landau-Lifshitz equation differs from the one that follows from the Maxwell equations in both the one-charge and two-charge cases. This last result does not support a recent statement by Rohrlich in favor of considering the Landau-Lifshitz equation as the correct and exact equation of motion for a point charge in classical electrodynamics.

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