By Topic

VLF pulse propagation in the magnetosphere

Sign In

Cookies must be enabled to login.After enabling cookies , please use refresh or reload or ctrl+f5 on the browser for the login options.

Formats Non-Member Member
$33 $13
Learn how you can qualify for the best price for this item!
Become an IEEE Member or Subscribe to
IEEE Xplore for exclusive pricing!
close button

puzzle piece

IEEE membership options for an individual and IEEE Xplore subscriptions for an organization offer the most affordable access to essential journal articles, conference papers, standards, eBooks, and eLearning courses.

Learn more about:

IEEE membership

IEEE Xplore subscriptions

2 Author(s)
D. Chang ; Hughes Aircraft Company, El Segundo, CA, USA ; R. Helliwell

Pulse distortion is important in controlled experiments on very low frequency (VLF) wave particle interaction (WPI) processes in the magnetosphere. Whistler-mode (WM) propagation of RF pulses through a homogeneous magnetoplasma as well as through a duct in the magnetosphere has been investigated by using the fast Fourier transform technique. This technique can be applied in both homogeneous and slowly varying media. As far as we know this is the first time that the distortion of a VLF pulse propagating in the magnetosphere has been calculated. In a homogeneous medium at frequencies below f_{H}/4 ( f_{H} is the electron gyrofrequency) the high frequency components arrive prior to the main body of the pulse while the low frequency components lag behind. This sequence is reversed when the carrier frequency exceeds f_{H}/4 . The distortion increases as the frequency departs from f_{H}/4 . In the magnetosphere it is found that the frequency of minimum distortion is the "nose" frequency f_{N} , as expected. When the carrier frequency is below f_{N} the high frequency components of a pulse always arrive first at the equator and the distortions increase as the carrier frequency departs from f_{N} . Above f_{N} , on the other hand, there is always a location along the path where the pulse distortion is minimum. It is also found that the stretching of the front end of a pulse is large enough ( \sim30 ms for a pulse at 4 kHz traveling through a duct at 4 R_{E} ) to require compensatory pre- and postprocessing of signals in certain wave-injection experiments. An equalizer to compensate for the phase distortion introduced by the medium has been designed. Computer simulation results show that when the preprocessed signals arrive at the interaction region they have the prescribed waveforms. By the same principle the propagation distortion developed between the interaction region and the receiving site can also be removed.

Published in:

IEEE Transactions on Antennas and Propagation  (Volume:28 ,  Issue: 2 )