Micropulsations in the morning sector, 3. Simultaneous ground-satellite observations of 10- to 45-s period waves nearL= 6.6

Abstract

A search for simultaneous 10‐ to 45‐s waves at the synchronous orbit at the location of ATS 1 and at Tungsten, Northwest Territories, Canada (near the foot of the ATS 1 field line), during 1969 resulted in the identification of only one event. This event occurred near 0900–1000 LT and was identified as a Pc 3 event. By combining 1967 data from College, Alaska (near the same L shell as ATS 1), with ATS 1 data, 90 simultaneous events were identified. Analysis of 60 of these events led to the conclusion that Pi 1 are rarely, if ever, observed on the magnetic equator at synchronous orbit, even when Pi 1 activity is present on the ground near the conjugate point. Pc 3, on the other hand, are common at synchronous orbit. A statistical study of the Pc 3 occurring at ATS 1 during simultaneous College wave activity indicated characteristics similar to those observed at ATS 6.

ULF pulsations observed by the ETS-VI satellite: Substorm associated azimuthal Pc 4 pulsations on the nightside

“…The two main frequency bands involved in the azimuthal Pc 3 pulsation, that is, the high (∼40 mHz) and low (∼20 mHz) frequency bands, are also found in the results by Arthur and McPherron (1977).…”

“…Arthur and McPherron (1977) found a strong midmorning peak in the occurrence distribution of Pc 3 pulsations observed by the ATS-1 geosynchronous satellite. Analyzing data from the geosynchronous satellites, Takahashi and McPherron (1984) presented occurrence probability of the azimuthally polarized harmonic waves, which shows a high occurrence on the dayside and a peak before local noon.…”

“…A brief review of the previous studies employing satellite data which were published before 1989 is found in Anderson et al (1990a). Arthur and McPherron (1977) studied statistically 81 events of transverse Pc 3 pulsations observed by ATS-1, which were simultaneously observed on the ground. The transverse Pc 3 pulsations had the local time distribution with a strong midmorning peak and dominant frequencies between 40 mHz and 50 mHz.…”

A Study of the Association of Pc 3, 4 Micropulsations with Interplanetary Magnetic Field Orientation & Other Solar Wind Parameters.

“…(Southwood, 1974), have been recorded at synchronous orbit (Arthur et al, 1977c;Hughes et al, 1978) and on the ground Lanzerotti et al,, 1972;Olson and Rostoker, 1978); and at both, simultaneously (Arthur and McPherron, 1977a); solar wind velocity has been positively correlated with ground pulsations (Saito, 1964;. It is important to mention that most of the cases analyzed by Lanzerotti et al (1972) gave polarization behavior contrary to that predicted by Southwood (1974), but consistent with .…”

Pulsating phenomena of auroral-zone X-rays associated with quasi-periodic VLF emissions and Pc 3 magnetic pulsations.

“…In association with these X-ray and auroral pulsations phenomena, Pi 1 magnetic pulsations are usually observed on the ground ARNOLDY et al, 1982). This type of magnetic pulsation, however, has not been found near the magnetic equatorial plane in the magnetosphere even if VLF emissions are observed there (ARTHUR and MCPHERRON, 1977;TSURUTANI and SMITH, 1977). Therefore, it has been suggested that Pi 1 pulsations are regarded as induction fields produced by overhead ionospheric currents (ARNOLDY et al, 1982).…”