Spectral structure and generation mechanism of ducted VLF whistler mode sideband waves

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1990

OSTI ID:6174034

Desa, L A.D.

An accurate determination is made of the sideband structure of ducted VLF whistler mode waves transmitted from Siple Station and observed at Lake Mistissini, Quebec. Single- and double-frequency transmissions are analyzed. Single-frequency sidebands are shown to be due to interactions between the input wave and harmonics of 60 Hz present within the duct. Sideband spectra are explained as due to wave-wave interactions occurring in the magnetosphere through electron cyclotron resonances, the line intensities required for such interactions being low. Resonances can be located outside or inside the wave potential wells. Application of the KAM theorem to the electron equations of motion shows the possible sideband radiation frequencies. Both external and trapped resonances generate the same radiation spectrum with frequencies given by a very simple formula. The carrier trapping frequencies do not affect the sideband wave frequencies, and do not impose sharp constraints on either the spectrum bandwidth, the sideband line separation, or the maximum interacting carrier frequency separation. It was found that the inhomogeneity of the magnetic field of the earth introduces phase shifts on the equilibrium positions of the resonances discussed. Those phase shifts, whether time dependent or not, will be translated at the receiving station as frequency shifts in the observed sidebands. A strong enough inhomogeneity will destroy a resonance completely. It was found that trapped resonances are much more resilient to the effects of the inhomogeneity than external resonances, this being the reason why extremely weak carriers can produce sizable and readily observable sidebands when they interact with stronger carriers.

• Research Organization: Stanford Univ., CA (USA)
• OSTI ID: 6174034
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BREMSSTRAHLUNG
CYCLOTRON RADIATION
CYCLOTRON RESONANCE
DATA
DIFFERENTIAL EQUATIONS
DUCTS
EARTH ATMOSPHERE
EARTH MAGNETOSPHERE
ELECTROMAGNETIC RADIATION
ELECTRON MOBILITY
EQUATIONS
EQUATIONS OF MOTION
HARMONICS
INFORMATION
MAGNETIC FIELDS
MOBILITY
NOISE
NUMERICAL DATA
OSCILLATIONS
PARTIAL DIFFERENTIAL EQUATIONS
PARTICLE MOBILITY
RADIATIONS
RADIO NOISE
RADIOWAVE RADIATION
RESONANCE
SPECTRA
THEORETICAL DATA
TRAPPING
WHISTLERS