RESEARCH ON RADIATION FIELDS ASSOCIATED WITH WHISTLERS

Directions of arrival of atmospheric whistlers was determined using three stations located on the ground. The method is described and the accuracy is evaluated. The necessity of fre quency selective operation is shown and the choice of bandwidth discussed. Equipment de signed to operate over long bases of the order of magnitude of a wavelength is described and preliminary results presented. The direction of arrival is generally close to the direction of the magnetic field but horizontally incoming whistlers are occasionally observed. Evidence is given that the wave front cannot be always con sidered as plane and a five stations network is necessary to ascertain of the planeity of the wave. An electronic computer which can be used to measure the very short transit times as sociated with short bases 1,00-o 2,000 feet long is described. The performances obtained in laboratory are satisfactory except for a rather small dynamic range. (Author)