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The problem of the approximation of the HE(11) radiation pattern by a Gaussian distribution is discussed. A numerical comparison between the HE(11) far-field theoretical pattern and the Gaussian approximations, derived by Abrams and by Crenn, permits an evaluation of the precision of these approximations. A new optimised HE(11) Gaussian approximation is calculated : the value of r(0) = 0.421a (or w(0) = 0.596a) for the beam radius at the waist is demonstrated to give the best HE(11) Gaussian approximation in the far-field and is very close to the result given by Crenn, while the Abrams value is less precise. The calculations are extended to the near-field. Universal curves for intensity, amplitude and power distribution are given for the HE(11) radiated mode. These results are of interest for laser waveguide applications and for plasma ECRH transmission systems.

Additional information

Authors: REBUFFI L, NET Team, Max-Planck-Institut für Plasmaphysik, Boltzmann Strasse 2, D-8046 Garching bei München (DE);CRENN J P, CEA, Département de Recherches sur la Fusion Contrôlée, 13108 Saint-Paul-lez-Durance (FR)
Bibliographic Reference: Article: International Journal of Infrared and Millimeter Waves, 1989, pp. 291-311
Record Number: 198911027 / Last updated on: 1994-12-01
Original language: en
Available languages: en
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