| Auroral and Sub-Auroral Interaction at the F Region Ionosphere |
31 AUG 89 |
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| Authors:
Jules Aarons; Michael Mendillo; BOSTON UNIV MA DEPT OF ASTRONOMY
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 | Deterioration of satellite signals and fading on HF are results of the appearance of intense irregularities of the order of meters to several hundred meters in the F layer. At auroral and sub-auroral latitudes the irregularities become intense and create serious problems. The interaction of the ionosphere during magnetic storms has been studied at auroral and subauroral latitudes. Results include a model which shows the expansion during the injection phase ... |
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| Dynamics of Small and Large Scale Irregularities at Sub-Auroral Latitudes |
10 OCT 87 |
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| Authors:
Jules Aarons; Michael Mendillo; BOSTON UNIV MA DEPT OF ASTRONOMY
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| In order to study the dynamics of ionospheric F-layer irregularities at latitudes below the auroral oval, radio, optical, and incoherent scatter observations were initiated primarily in the region of 75 degrees W longitude. In addition earlier observations including in-situ satellite measurements were used, The principal conclusions were first that the sub-auroral ionospheric observations could be understood by correlating F-layer irregularities with ring current intensities as measured by Dst, the magnetic ... |
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| Geomagnetic Pulsation Studies Using the AFGL Magnetometer Network |
JUN 87 |
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| Authors:
W. J. Hughes; BOSTON UNIV MA DEPT OF ASTRONOMY
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| This contract funded a study of geomagnetic pulsations, the lowest frequency waves which occur naturally in the Earth's magnetosphere. The study used as its primary data source the AFGL Magnetometer Network which recorded midlatitude and subauroral magnetic variations continuously for six years. The major aim of the study was to develop Pi2 pulsations which occur at substorm onset, as monitors and locators of magnetospheric activity. Other aims of the study ... |
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| Magnetic Storm Effects on F Layer Irregularities Near the Auroral Oval, |
MAY 1987 |
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| Authors:
Jules Aarons; Alan S. Rodger; BOSTON UNIV MA DEPT OF ASTRONOMY
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| The effect of F layer irregularities on trans-ionospheric transmissions and fading at HF at equatorial, auroral, and polar latitudes has been documented. Little has been done on morphology and physics of irregularities noted at sub-auroral latitudes, in the vicinity of the plasmapause. The intensities of the irregularities are considerably less than those observed at equatorial and high latitude regions. The scatterers in this region are at times correlated with magnetic ... |
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| A Model for the Low-Latitude Ionosphere with Coefficients for Different Seasonal and Solar Cycle Conditions |
01 NOV 86 |
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| Authors:
Michael Mendillo; Bruce Herniter; BOSTON UNIV MA DEPT OF ASTRONOMY
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| A new ionospheric model for the low latitude ionosphere has been constructed to provide easy access to electron density profiles (Ne(h)), total electron content (TEC) and 6300A airglow under a variety of conditions. The results from the rigorous theoretical calculations for ionospheric structure at a given time and a site were parameterized to a set of six coefficients that reproduce the individual Ne(h) profiles using a simple algebraic formula. In ... |
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| The Dynamics of Equatorial F Layer Irregularities |
30 JUN 85 |
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| Authors:
J. Aarons; M. Mendillo; BOSTON UNIV MA DEPT OF ASTRONOMY
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| Contents: Introduction to Equational Irregularities; Research Studies: (A) Ascension Island Observations and Analysis; (B) Empirical Model to Forecast Scintillation at 250 MHz along Magnetic Equator; (C) Magnetic Bay Triggering of Irregularity Patches; (D) Patch Walls; (E) Natal, Brazil, Observations and Analysis; (F) Simulation/Verification; Conclusions; Future Studies; Publication Summary. |
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| Polarization Patterns of Pi 2 Magnetic Pulsations and the Substorm Current Wedge |
01 OCT 1983 |
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| Authors:
M. Lester; W. J. Hughes; BOSTON UNIV MA DEPT OF ASTRONOMY
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| Optical, Radio and Computer Simulation Studies of the Brazil Ionospheric Modification Experiment of 8 September 1982 |
31 JUL 1983 |
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| Authors:
J. Baumgardner; M. Mendillo; B. Herniter; H. Spence; BOSTON UNIV MA DEPT OF ASTRONOMY
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| The Brazil Ionospheric Modification Experiments (BIME) provided an opportunity to conduct simultaneous airglow and electron content observations during a space plasma active experiments campaign in Natal, Brazil, in September 1982. A period of background data was also obtained, and computer simulation studies were conducted for the background and artificially disturbed conditions. The BIME -1 release produced a depletion in TEC of 1-1.5 TEC units that was accompanied by an airglow ... |
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| A Study of Geomagnetic Pulsations Using the AFGL (Air Force Geophysics Laboratory) Magnetometer Network |
13 JAN 1983 |
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| Authors:
W. J. Hughes; H. J. Singer; M. Lester; BOSTON UNIV MA DEPT OF ASTRONOMY
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| The objective of this work has been to study the midlatitude magnetic signatures of magnetospheric substorm onsets with the aim of using these signals to time and locate substorm onsets. The primary data source was the AFGL magnetometer Network, a unique facility in that it spans over four hours in local magnetic time, a far greater extent than any other high-time-resolution network. Using this capability we have found that pi2 ... |
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| Airglow Imaging Studies of Natural and Artificially Induced Ionospheric Disturbances |
FEB 1982 |
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| Authors:
Michael Mendillo; Jeffrey Baumgardner; Harlan Spence; BOSTON UNIV MA DEPT OF ASTRONOMY
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| A low light level, image intensified airglow monitoring system has been developed for ground-based studies of 6300A airglow characteristics of equatorial plasma depletions and rocket exhaust induced ionospheric holes. The system was designed for narrow band interference filters (6 A FWHP) with interchangeable all-sky (180 deg) and narrow field (60 deg) lenses; it records images photographically using a standard 35mm camera. In addition to the morphology features capable of being ... |
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| Radio Studies of Coronal Holes |
MAR 1981 |
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| Authors:
Michael D. Papagiannis; Kile B. Baker; BOSTON UNIV MA DEPT OF ASTRONOMY
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| This report describes all the projects undertaken during the entire period of the above contract, the scope of which was to study coronal holes at radio wavelengths. Chapters 1, 2 and 3 summarize work that has already been described in our previous scientific reports and published papers. Chapters 4 and 5 and comprehensive descriptions of the more recent work that has not been previously published. Chapter 1 describes the determination ... |
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| Correlation of High Latitude Coronal Holes with Solar Wind Streams High Above or Below the Ecliptic, |
APR 1980 |
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| Authors:
Kile B. Baker; Michael D. Papagiannis; BOSTON UNIV MA DEPT OF ASTRONOMY
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| This report has correlated the positions of high latitude coronal holes as determined from the Helium 10830 A spectroheliograms, with the velocities of solar wind streams high above or below the ecliptic, which could have originated from the same positions as the coronal holes. The solar wind speeds were determined from interplanetary scintillation (IPS) measurements made at the University of California at San Diego and at the Toyokawa Observatory in ... |
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| Short Term Periodicities in Ionospheric Total Electron Content. |
MAR 1980 |
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| Authors:
Kenneth H. Schatten; Michael Mendillo; BOSTON UNIV MA DEPT OF ASTRONOMY
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| Short-term variability of the ionospheric F-region has been studied using total electron content (TEC) data from several North American sites. Specific attention was given to lunar-induced periodicities in TEC and to a general treatment of changes in TEC associated with variations in the height of the F-region (hmF2). In both cases, simple analytical expressions were derived from statistical analysis of the large TEC and hmF2 data bases. These relations are ... |
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