[en] The long-line technique for measuring ionospheric convection was developed for use at high midlatitudes. In this study it was employed near the auroral zone (62 deg Lambda). Measurements are very comparable with those from other techniques. The convection patterns were found to be dominated by fluctuation with periods of several minutes to several hours and spatial extent greater than 500 km but less than 1500 km. The convection was quite different on quiet and on disturbed days. 6 references

[en] The lengths of irregularities which produce 150-MHz amplitude scintillations have been measured at 43 deg N, 81 deg W (geographic) using arrays of receivers with large spacings. The average length (major axis radius) of the irregularities was 6.1 km. This is much shorter than expected and implies that the measurements are of 'young' irregularities, less than 1 minute old. These irregularities appear to be a large, 25-50-percent perturbation of the background density. 8 refs

[en] Arrays of 15 receivers were used to study scintillation irregularities in the ionospheric F region using Navy Navigational Satellites at 150 MHz as sources. The principal irregularities are characterized by parallel striations with sharply defined edges and thin traces. The narrow striations indicate the presence of irregularities alligned along the earth's magnetic field. The form of the height distribution, similar to that of an F region electron density profile, leads to the conclusion that the scintillation irregularities extend throughout most of the F region. The proposed model suggests a way of mapping the irregularities

[en] Three years' observations of the Hilat satellite from stations Sondre, Churchill, and Tromso have been used to study the distributions of scintillations over the northern polar region. Two regions showed enhancement. Region (1) was an enhancement of phase scintillations when the line of sight to the satellite lay along an L shell and the observing station was under the auroral oval. Region (2) is revealed most clearly by amplitude scintillations and maximizes in an annular region several degrees poleward of the auroral oval. Region (1) is most likely associated with large-scale 'blobs' of ionization in the auroral zone; region (2) appears to be due to km-scale irregularities generated in the polar cap. 17 refs

[en] Scintillation and other measurements from the HILAT program were used to study the zone at the edge of the polar cap where the most intense average scintillations are found. The maximum of the zone was found to be horseshoe shaped and located on the dayside. This scintillation zone shows only small variations with season and magnetic activity. On individual HILAT passes discrete onsets of intense scintillations are observed. Averaging to these onsets gives the high average scintillation intensities. The onsets appear to occur where irregularities are being created. These same locations show an increase in ionospheric electron content and an increase in the low energy electron flux. After creation the irregularities are convected towards the polar cap. The irregularity source region is also the region known as the 'dayside high-latitude auroral region' where the precipitating soft electron flux produces 630 nm auroras. (author)

[en] Observations of the NW-SE component of F region convection obtained with a scintillation drift experiment have been compared with power and Doppler velocity measurements of auroral E region coherent backscatter at 50 MHz made with the Bistatic Auroral Radar System (BARS), which is able to observe only at large magnetic aspect angles. It was found that E region backscatter was observed only when the NW-SE component of the F region drift was in the SE direction. This and other observations are shown to be consistent with a recently proposed explanation for these large aspect angle VHF backscatter observations, based on refraction through auroral ionization structures in the E region. In most cases the vector velocity derived from BARS observations had a magnitude substantially below that inferred from the scintillation measurements. Observations during one period were noticeably different from the others, with unusually small Doppler velocities

[en] A two-station experiment was conducted in Ontario and Saskatchewan using a long east-west baseline to examine properties of scintillation activity in the region of the ionospheric trough. Scintillations were also measured using radio stars, and auroral convection was monitored during active periods of a region which centered on 103 deg W, 59 deg N. During August, 1980, scintillation enhancements had an average patch size of about 500 km east-west, with a much smaller size in the north-south direction. Electric fields did not have a significant effect, and auroral patches were found to have many properties similar to those of scintillation patches, which indicates an association

[en] The results obtained from the differential phase measurements made during the Waterhole experiment are described. While there is evidence that the electron concentration in the immediate neighbourhood dropped as expected, the more dramatic outcome was the sudden cessation of particle precipitation. The radio measurements show that the electron concentration in the E-region below the 'hole' began to decay at the time of the explosion with a rate which is consistent with recombination. It continued to decay over the time that it could be observed, about 2.5 min. It must be concluded that the particle precipitation along magnetic field lines through the hole was cut off for at least that length of time

[en] Ionospheric E x B convections are measured by a new technique that uses satellite scintillations. The measurements are for and ionospheric region centred on 39⁰N, 82⁰W geographic or 53⁰ invarient latitude. Results are presented for spring equinox 1980. The quiet condition eastward convection drift is approximately V/sub i/E = -12+43 cos(2π/24)(t-13.4). During disturbed conditions at nighttime the westward convection becomes large and highly variable. The northward perpendicular E x B convection is approximately V/sub i/N = -5+13 cos (2π/12)(t-10.5)+6 cos (2π/24) (t-11.5) m/s during quiet conditions. During disturbed conditions the semidiurnal component of the northward convection increases by about a factor of 3 and becomes larger than the diurnal

[en] The time-history of particle energies and fluxes associated with pulsating auroras in the morning sector is derived from ionosonde measurements. All the pulsating auroras studied showed a similar history with the pulsations occurring during a time interval of the order of an hour during which the average auroral Maxwellian characteristic energy stays relatively constant but the energy flux decreases progressively during the event. A possible explanation for this behaviour in terms of an injection of particles into a magnetospheric 'bottle' near the midnight meridian and the progressive precipitation out of the bottle during the pulsating event is suggested. (auth)