| Ionospheric Irregularities: Source, Structure, Plasma Processes and Effects on Sensor Systems |
31 OCT 89 |
230 pages |
| Authors:
Sunanda Basu; Cesar Valladares; Eileen MacKenzie; Clifford Bryant; Patricia Doherty; EMMANUEL COLL BOSTON MA
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 | A multi-technique approach has been used at a number of geophysically interesting locations to determine various sources of high-latitude irregularities, their occurrence characteristics and effects on sensor systems. Auroral scintillation morphology and irregularity anisotropy were determined using HiLat satellite data obtained at Tromso. Global scintillation characteristics were determined as a function of the sunspot cycle and a high latitude scintillation review was prepared reflecting our improved understanding of different sources ... |
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| Ionospheric Scintillations and In-Situ Measurements at an Auroral Location in the European Sector |
04 OCT 1988 |
15 pages |
| Authors:
Santimay Basu; Sunanda Basu; Eileen MacKenzie; Dan Weimer; EMMANUEL COLL BOSTON MA
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| The orbiting HiLat satellite offered a unique opportunity for studying the ionospheric scintillation parameters in relation to the in-situ measurements of ionization density, drift velocity, field-aligned current, and particle precipitation during the sunspot minimum period. This paper discusses the results of such a morphological study based on observations at the auroral oval station of Tromso, Norway. The dynamics of the spatial and temporal extent of this region are illustrated in ... |
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| Ionospheric Constraints on VHF/UHF Communications Links during Solar Maximum and Minimum Periods |
Jun 1988 |
17 pages |
| Authors:
Santimay Basu; E MacKenzie; Sunanda Basa; EMMANUEL COLL BOSTON MA
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| An extensive VHF/UHF scintillation data base covering the frequency range of VHF to a few gigahertz has been utilized to determine the magnitudes of phase and intensity scintillations and their temporal/spatial structures during the sunspot maximum and minimum periods. The equatorial portion of the study has been based on geostationary satellite observations at Huancayo, a station on the magnetic equator, and at Ascension Island, which is an equatorial anomaly station ... |
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| Solar Cycle Variation of Long Duration 10.7 CM and Soft X-Ray Bursts |
16 May 1988 |
12 pages |
| Authors:
S Kahler; E W Cliver; EMMANUEL COLL BOSTON MA
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| Gradual rise-and fall (GRF) microwave bursts and long duration soft X -ray events (LDEs) are generally accompanied by solar coronal mass ejections (CMEs). We use reports from the Ottawa and Penticton stations to examine the annual variations from 1965 to 1985 of 10.7 cm GRF bursts with total durations of at least 4 hr. The annual numbers of such bursts are well correlated with the quiet-Sun 10.7 cm flux densities. ... |
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| Satellite Instrument Development and Data Analysis |
30 SEP 87 |
116 pages |
| Authors:
Louise Gentile; Ernest Holeman; Alan Huber; Stephen Kahler; John Pantazis; EMMANUEL COLL BOSTON MA
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| This contract has supported research in the areas of Software, Hardware, Theory, and Modelling. Each of these four areas has been developed in concert with the other three. Consequently, the on-going effort has been totally integrated in its results, with changing emphases across these areas as work progressed. This report, therefore, treats each area separately, and consists - in large part- in the presentation of published reports reports which occurred ... |
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| Structures of Density and Velocity Fluctuations in the Auroral Oval and Their Impact on Communication and Radar Systems |
MAY 87 |
16 pages |
| Authors:
Sunanda Basu; Santimay Basu; W. R. Coley; N. C. Maynard; EMMANUEL COLL BOSTON MA
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| A new class of ionospheric irregularities in the auroral oval associated with large structured plasma flows has been recently isolated with radar and satellite in-situ measurements. These density irregularities have large power spectral densities (psd) at short scale lengths (approx. hundreds to tens of meters). The paper characterizes the density and velocity spectra in such regions and discusses their impact on scintillation observations and radar performance. The structured plasma flows ... |
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| Multi-Technique Study of Ionospheric Structures Causing Degradation in Trans-Ionospheric Communications Systems |
20 APR 87 |
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| Authors:
Sunanda Basu; Patricia Doherty; Eileen MacKenzie; M. P. Hagan; EMMANUEL COLL BOSTON MA
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 | Multiple diagnostics have been used at different latitude regimes of the globe to probe large and small scale ionospheric structures which cause degradation in trans-ionospheric communication systems. It was determined that the equatorial anomaly crest had the most disturbed F-region irregularity environment giving rise to saturated GHz scintillation and phase scintillations as large as 16 radians at 244 MHz. At the magnetic equator a host of techniques during the Project ... |
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| 250 MHz/GHz Scintillation Parameters in the Equatorial, Polar and Auroral Environments |
28 MAR 86 |
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| Authors:
Santimay Basu; E. MacKenzie; Sunanda Basu; E. Costa; P. F. Fougere; EMMANUEL COLL BOSTON MA
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| Ionospheric scintillation effects encountered in the equatorial anomaly crest, polar cap and auroral regions have been contrasted to provide information for the design and evaluation of the performance of satellite communication links in ghese regions. The equatorial anomaly region is identified as the most disturbed irregularity environment where the amplitude and phase structures of VHF/L-band scintillations are primarily dictated by the strength of scattering rather than ionospheric motion. In the ... |
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| Equitorial Scintillations: Advances Since ISEA-6 |
JAN 85 |
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| Authors:
S. Basu; EMMANUEL COLL BOSTON MA
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| Since the last equatorial aeronomy meeting in 1980, our understanding of the morphology of equatorial scintillations has advanced greatly due to more intensive observations at the equatorial anomaly locations in the different longitude zones. The unmistakeable effect of the sunspot cycle in controlling irregularity belt width and electron concentration responsible for strong scintillation in the GHz range has been demonstrated. The fact that night-time F-region dynamics is an important factor ... |
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| Technique for Producing a Coherent Sum of the Data from P78-1, F2, and F4 Satellites |
MAY 1983 |
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| Authors:
Ernest G. Holeman; EMMANUEL COLL BOSTON MA
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| Vertically incident data from the P78-1 J sensor was made available during the first quarter of 1983. It was sorted into a grid and time frame compatible with the F2 and F4 statfile data. In order to produce a coherent sum of the data from the three satellites into a final statfile product a consensus solution to several problems was agreed to. (Author) |
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| Geomagnetic Pulsations-Production/Interpretation |
SEP 1982 |
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| Authors:
Elwood Maple; EMMANUEL COLL BOSTON MA
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| Work has been devoted to experimental studies of middle-latitude geomagnetic pulsations in the period range 0.2 to 50 minutes. The principal effort has been on the resonant periods of the pulsations which arise from hydromagnetic resonances in the magnetosphere. The resonant periods appear as peaks in the period distributions and frequency spectra of the pulsations. The present work utilizes polarization traces which provide continuous displays of the polarization of the ... |
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| Phase and Amplitude Scintillation Statistics at 244 MHz from Goose Bay Using a Geostationary Satellite |
06 AUG 1982 |
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| Authors:
Sunanda Basu; Santimay Basu; Robert C. Livingston; Eileen MacKenzie; Herbert E. Whitney; EMMANUEL COLL BOSTON MA
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| Phase and amplitude scintillation measurements made at 244 MHz from Goose Bay using the geostationary satellite Fleetsat are presented. An extended dynamic range receiver with an extremely stable local oscillator measured the phase variations with the precision of a coherent system subject to certain limitations. The data were obtained for a 10-month period in 1979 during a high sunspot epoch to extend the limited temporal coverage of the orbiting Wideband ... |
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| The Plasma Experiment on Board Meteosat-F2 |
AUG 1982 |
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| Authors:
A. Huber; J. Pantazis; D. R. Parsignault; P. L. Rothwell; A. D. Johnstone; EMMANUEL COLL BOSTON MA
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| An electron spectrometer has been designed to aid in the study of spacecraft charging on METEOSAT-F2. Differential energy analysis is performed by a pair of electrostatic analyzers (ESA) in which a time-sequenced variable electrostatic field deflects electrons of selected energies toward an exit aperture where they are counted by Channeltron Electron Multipliers (CEM). The small ESA covers energies ranging from 50 eV to 1 keV to 20 keV. The dwell ... |
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| Comparison of Ionospheric Scintillation Statistics from the North Atlantic and Alaskan Sectors of the Auroral Oval Using the Wideband Satellite |
15 SEP 1981 |
133 pages |
| Authors:
Sunanda Basu; Santimay Basu; Robert C. Livingston; Herbert E. Whitney; Eileen MacKenzie; EMMANUEL COLL BOSTON MA
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| Phase and amplitude scintillation measurements made at 138 MHz at two widely separated auroral stations, Goose Bay, Labrador, and Anchorage, Alaska, are presented. The phase coherent transmissions obtained from the sun- synchronous Wideband satellite were used for this purpose. The data were obtained for part of the year 1979 during a high sunspot epoch and was terminated by the failure of the Wideband satellite in August, 1979. The primary objective ... |
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| Modelling of Equatorial Phase and Amplitude Scintillations from OGO-6 and AE Irregularity Data. |
NOV 1979 |
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| Authors:
Sunanda Basu; Santimay Basu; EMMANUEL COLL BOSTON MA
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| The technique of modelling equatorial phase and amplitude scintillations from in-situ measurements of irregularity amplitude, ambient ionization density and irregularity power spectrum is outlined. The in-situ measurements do not directly provide information on irregularity layer thickness for which radar backscatter observations are utilized. The equatorial scintillation models developed from OGO-6 and AE-C in-situ measurements during the two solstices are presented. Considerable differences in the longitude variation of scintillations are predicted ... |
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| Field Aligned E- and F-Layer Backscatter Observations |
JAN 1972 |
58 pages |
| Authors:
Sunanda Basu; Robert L. Vesprini; EMMANUEL COLL BOSTON MA
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| In a reanalysis of the HF (19 MHz) backscatter data from Plum Island MA, the occurrence of field aligned echoes from the E and F layers, called FAE(E) and FAE(F) respectively, was studied in detail. FAE(E) during quiet magnetic conditions (K(Fr)0-3) is a nighttime phenomenon with a definite maximum during the summer, when it is accompanied by groundscattered E(s). A weaker maximum is observed in the winter. |
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