Accession Number : ADA183748

Title :   Geomagnetic Pulsation Studies Using the AFGL Magnetometer Network.

Descriptive Note : Final rept. 1 Dec 83-28 Feb 87,

Corporate Author : BOSTON UNIV MA DEPT OF ASTRONOMY

Personal Author(s) : Hughes,W J

PDF Url : ADA183748

Report Date : Jun 1987

Pagination or Media Count : 26

Abstract : This contract funded a study of geomagnetic pulsations, the lowest frequency waves which occur naturally in the Earth's magnetosphere. The study used as its primary data source the AFGL Magnetometer Network which recorded midlatitude and subauroral magnetic variations continuously for six years. The major aim of the study was to develop Pi2 pulsations which occur at substorm onset, as monitors and locators of magnetospheric activity. Other aims of the study were to study the higher frequency types of continuous pulsation which are believed to be generated via ion cyclotron resonance in the radiation belt, and to develop data management and analysis software. These latter aims were in preparation for the up-coming CRRES mission. The midlatitude Pi2's are in a reliable indicator of substorms and their polarization pattern provides a good method of finding the local time of the main activity of a particular substorm. For small isolated substorms the center of the polarization pattern and the center of the midlatitude geomagnetic bay pattern produce by the dc substorm currents, coincide, but during more disturbed intervals this is not always true, as consecutive bays are not well separated from one another. The midlatitude signatures spatially relate the other various signatures of substorm onset seen at geosynchronous orbit and in the auroral zone. The main auroral surge forms about an hour west of the center of the Pi2 polarization pattern and the longitude at which the surge forms separates the region of space near geosynchronous orbit where the geomagnetic field becomes more dipolar from that where it becomes more taillike.

Descriptors :   *MAGNETOSPHERE, *GEOMAGNETISM, AURORAE, BAYS, COMPUTER PROGRAMS, CYCLOTRON RESONANCE, DATA MANAGEMENT, DIRECT CURRENT, EARTH(PLANET), FREQUENCY, INDICATORS, INTERVALS, IONS, ISOLATION, LOCATORS, MAGNETIC FIELDS, MAGNETOMETERS, MONITORS, NETWORKS, ORBITS, PATTERNS, POLARIZATION, PULSES, RADIATION BELTS, RELIABILITY, STORMS, TIME, WAVES, MAGNETIC STORMS, MAGNETIC SIGNATURES

Subject Categories : Atmospheric Physics
      Geomagnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE