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Description

A micropulsation recording program was carried out at College and Anchorage, Alaska and at Bar I, Canada, with induction magnetometers. The analysis program centered mainly on synoptic and polarization characteristic for types Pc 1-2, IPDP, and Pi burst micropulsation events. Summaries of the known morphological features for structured Pc 1 and unstructured Pc 1-2 micropulsations are given. The synoptic studies disclosed latitude relationships between unstructured Pc 1-2, IPDP, and Pi burst events. At the onset of a polar substorm, Pi bursts occur near midnight at 65°-70° geomagnetic latitudes. IPDP events follow the Pi burst and are seen in evening hours at 60°-65° latitudes. IPDP events seen in afternoon hours are often preceded by unstructured Pc 1-2 activity which maximizes a few degrees polewards of the IPDP. The IPDP events are seen in the evening “bulge” region of the plasmasphere. The proton plasma requirement for IPDP wave generation suggests that protons which are injected near midnight in the Pi burst event drift westwards into the bulge and generate unstructured Pc 1-2 and IPDPs there. The polarization characteristics of Pc 1 activity indicate that simple structured Pc 1 events originate on a stable tube of force. Unstructured Pc 1 events and events which are superpositions of several events usually display pronounced time-variability in the polarization characteristics.

Publication Date

1-17-1971

Keywords

Geomagnetic micropulsations

Handle

http://hdl.handle.net/11122/15440

Types Pc 1-2 and IPDP micropulsations at the auroral zone

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