Auroral and Midlatitude Radar Studies: Radar Methods for Improved Diagnostics of the HF-Modified and Natural Ionospheres.

This research program addresses fundamental issues related to the interaction of a high-power, high- frequency (3 - 10 MHz) radio wave with the ionosphere. Data acquired with incoherent scatter radars and a modest (50 kW) VHF radar were examined. The reported observations were made with the Arecibo...

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Bibliographic Details
Main Authors: Djuth, Frank T., Elder, John H., Williams, Kenneth L.
Other Authors: GEOSPACE RESEARCH INC EL SEGUNDO CA
Format: Text
Language:English
Published: 1996
Subjects:
Atmospheric Physics
Active & Passive Radar Detection & Equipment
*EXHAUST PLUMES
*RADAR SIGNATURES
*IONOSPHERIC DISTURBANCES
GUIDED MISSILES
HIGH FREQUENCY
COMPUTATIONS
PLASMAS(PHYSICS)
RADAR
CROSS SECTIONS
INCOHERENT SCATTERING
IONOSPHERIC MODELS
RADIO WAVES
STRATIFICATION
VERY HIGH FREQUENCY
LOW ALTITUDE
IONOSPHERIC MODIFICATION
LANGMUIR TURBULENCE
ION TURBULENCE
PE61102F
WUPL2310GJAA
Langmuir
Norway
Tromsoe
Online Access:http://www.dtic.mil/docs/citations/ADA314999
http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA314999
Description
Summary:This research program addresses fundamental issues related to the interaction of a high-power, high- frequency (3 - 10 MHz) radio wave with the ionosphere. Data acquired with incoherent scatter radars and a modest (50 kW) VHF radar were examined. The reported observations were made with the Arecibo HF modification facility in Puerto Rico and the Tromsoe 'superheater' located in Norway. Particular attention is paid to the excitation of Langmuir and ion turbulence and the development of induced ionospheric irregularities. Within 50 ms of HF beam turn on, the ionospheric plasma behaves as a smooth stratified medium. In this environment, elements of strong Langmuir turbulence are detected near the altitude where the HF frequency matches the local electron plasma frequency. The coupling between Langmuir oscillations and ionospheric perturbations is examined over both intermediate (50 ms to several seconds) and long time scales (tens of seconds and beyond) to elucidate HF energy partitioning in the plasma. An additional investigation focused on the physics of missile plumes in the lower atmosphere is also described. This can be viewed as a lower atmosphere modification experiment in which missile fuel generates a highly collisional plasma. Plume signatures were measured with a VHF radar to help verify model calculations of cross section and spectral content.

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