[en] The results of two Antarctic rocket campaigns, primarily initiated to investigate electron precipitation stimulated by signals from the Siple-Station ground-based VLF transmitter, are presented. While the primary objective of the campaigns was not achieved, the Siple VLF transmitter facilitated a study of the wave environment in the ionosphere. Standing wave patterns in the ionosphere were observed for the first time by detectors flown aboard the Nike-Tomahawk rockets; the same detectors monitored a continuous signal from the transmitter through the neutral atmosphere and into the ionosphere, providing unique data for comparison with theoretical studies of wave propagation. The measurements of penetrating electron precipitation were interpreted in terms of a model of energetic electron precipitation from the trapped radiational belts. 52 references

[en] The ionospheric electric field data that was obtained by the 1985-1986 South Pole balloon campaign is being searched for evidence of the ionospheric signature of flux transfer events (FTEs). The objective of the search is to compile a list of events that can be compared with the various competing models of FTE ground signatures. This paper will present 6 hours of data centered on local magnetic noon on 7 January 1987. At least three candidate events can be seen in these data

[en] Measurements of the X-ray bremsstrahlung precipitation were made during the Araks experiments. The following conclusions were deduced from the data: with several exceptions the ambient X-ray flux observed was the normal quiet background expected for the location and existing conditions. The X-ray flux at energies below 20 keV was in excess of that predicted by theory. No obvious effects of the Araks experiments were seen in the data. However, a superposed epoch analysis of the X-ray data revealed a very small amount of precipitation associated with the electron gun

[en] A simple model is outlined to describe electron precipitation from the population of charged particles trapped in the Earth's magnetic field; almost all of the precipitation is shown to occur in the region of the South Atlantic Anomaly (SAA). When the effect of a dawn-to-dusk electric field across the magnetosphere is included in the model, a diurnal modulation of the precipitated electron flux is predicted. Experimental evidence which supports the diurnal modulation model is described. The resulting diurnal variation in atmospheric conductivity in the SAA is shown to be such that it could account for part of the daily UT variation in the geoelectric field. The observed seasonal variation in the pattern of geoelectric field modulation is also shown to be consistent with the proposed source of the daily variation. The difficulty of altering global conductivity by intense ionization of the mesosphere is discussed. (author)

[en] The study of the perturbation of the ionosphere by upper-atmospheric neutral waves has been a subject of major interest for more than 30 years. The initial energy source for these waves in weather activity in the troposphere. In the absence of dissipation, neutral waves propagating upward through an atmosphere with exponentially decreasing density will grow exponentially in amplitude due to the conservation of energy. In the E layer of the ionosphere, collisions keep the ions coupled strongly to the neutral gas, whereas the electron-neutral collisions have become so infrequent that the electrons are magnetized and held fixed with respect to the Earth's magnetic field. Therefore, in the E layer, neutral wind fluctuations will move the ions with respect to the electrons, thus driving currents and building up space charge to create an electric field. Historically, this topic has been investigated at mid- and low-latitude because auroral processes can easily dominate the atmospheric dynamo signature at higher latitude (Mozer 1971). Recent evidence suggests that neutral wave-driven dynamo fields can be an important signal source at high-latitude during geomagnetically quiet times (Earle and Kelly 1987); however, Earle and Kelley's argument was based on statistical comparison of spectral shapes. Simultaneous direct observations of lower atmosphere neutral-wind waves and upper atmosphere electric fields were lacking. This paper will present an example of just such an observation

No abstract available

[en] On January 4, 1978, at 1140 UT, a SuperArcas sounding rocket was launched from Siple Station, Antarctica (L = 4.2, 76⁰S, 84⁰W), during a geomagnetically disturbed period (Kp = 6--) with intense X ray and VLF chorus activity. The parachuted payload observed an intense microburst precipitation event of 10-minute duration. These data have been correlated with measurements of VLF chorus by receivers on the ground at both Siple and its magnetic conjugate point, Roberval, Quebec. Detailed one-to-one correspondence between the microbursts and the chorus was not a consistent feature of the data. Time series analysis of the data did indicate a significant correlation between the Siple X ray precipitation and the Roberval VLF waves with an arrival time delay of 0.1 +- 0.3 seconds

[en] A comparison is made between the measured muon energy spectrum at sea level and that predicted by four theoretical models (namely, Maeda-Cantrell (MC), constant energy (CE), Cocconi-Koester-Perkins (CKP) and scaling models). It is concluded that the scaling model agrees with the experimental data at energies less than 100 GeV, and the CKP model provides the best description of the spectrum at energies above 100 GeV

No abstract available

[en] The absolute vertical cosmic ray muon spectrum is investigated theoretically. Models of high energy interactions (namely, Maeda-Cantrell (MC), Constant Energy (CE), Cocconi-Koester-Perkins (CKP) and Scaling Models) are used to calculate the spectrum of cosmic ray muons at sea level. A comparison is made between the measured spectrum and that predicted from each of the four theoretical models. It is concluded that the recently available measured muon differential intensities agree with the scaling model for energies less than 100 GeV and with the CKP model for energies greater than 200 GeV. The measured differential intensities (Abdel-Monem et al.) agree with scaling. (orig.)