Lightning--induced electron precipitation events observed at L-2. 4 as phase and amplitude perturbations on subionospheric VLF signals

Journal Article · Wed Apr 01 04:00:00 EST 1987 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JA092iA04p03293· OSTI ID:6581317

Inan, U S; Carpenter, D L

Lightning-induced electron precipitation (LEP) events are studied using the Trimpi effect, in which the precipitation-induced ionization enhancements in the lower ionosphere (D region) give rise to rapid perturbations of subionospheric VLF signals. In 1983,the phase and amplitude of signals from the NPM transmitter in Hawaii (23.4 kHz) and the Omega transmitter in Argentina (12.9 kHz) were measured at Palmer, Antarctica (L-2.4), together with the magnetospheric whistler background. The long baseline and over-sea great circle paths from these two sources make it possible for the observed perturbations to be interpreted using a single waveguide mode theory. Analytical expressions are used to relate the magnitude of the phase perturbations to differential changes in ionospheric reflection height along a segment of the propagation path. The predicted relationship between relative perturbation sizes on the two different signals is compared with measurements. From this information, the whistler-induced flux levels are inferred to be in the 10/sup -4/--10/sup -2/ erg cm/sup -2/ s/sup -1/ range and the precipitation regions are inferred to be roughly ''circular'' in shape, rather than elongated along L shells. Measured amplitude changes tended to be small (--0.5 dB) and negative, as expected from a single-mode theory, but the ratios of simultaneous amplitude and phase perturbations were slightly larger than the theory predicts, probably due to the effects of an additional mode(s). An assessment of the relative detectability of amplitude versus phase perturbations favors phase perturbations by -- 10 dB, irrespective of the detection scheme used. copyright American Geophysical Union 1987

• Research Organization: STAR Laboratory, Stanford University, Stanford, California
• OSTI ID: 6581317
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 92:A4; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
CHARGED-PARTICLE PRECIPITATION
D REGION
EARTH ATMOSPHERE
ELECTRIC DISCHARGES
ELECTROMAGNETIC RADIATION
ELECTRON PRECIPITATION
IONIZATION
IONOSPHERE
LIGHTNING
NOISE
PLANETARY IONOSPHERES
RADIATIONS
RADIO NOISE
RADIOWAVE RADIATION
REFLECTION
WAVE PROPAGATION
WAVEGUIDES
WHISTLERS