DSIR , Lower Hutt , New Zealand * *

  title={DSIR , Lower Hutt , New Zealand * *},
  author={J. Geomag and Michael K Andrews and Louis J. Lanzerotti and Carol G. Maclennan and Bell Laboratories},
We show that the Doppler shift on whistler mode signals from VLF transmitters may be used to infer the magnetic field of an hydromagnetic wave above the ionosphere in the magnetosphere. This inferred field can then be compared with that measured on the ground. We examine one event in detail and show the data imply that a it/2 rotation of the orientation of the wave ellipse has occurred between the magnetosphere and the ground.