| IRIS Diagnoses of Man-Made and Naturally-Occurring Ionospheric Plasma Turbulence |
01 MAR 2005 |
22 pages |
| Authors:
Min-Chang Lee; MASSACHUSETTS INST OF TECH CAMBRIDGE PLASMA FUSION CENTER
|
 | Radio wave experiments have been conducted at Arecibo, Puerto Rico and Gakona, Alaska together with numerical analyses aimed at investigating man-made and naturally-occurring ionospheric plasma turbulence. Research progress and results reported include the following. (1) Ionospheric ELF and VLF experiments in Alaska discover that a horizontal Hertzian magnetic dipole (HMD)) with a radius of about 7 km at an altitude around 70 km is responsible for the generation of ELF/VLF ... |
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| Arcjet Plasma Neutralization of Hall Thrusters I: Hybrid Thruster Mission Analysis |
10 MAR 2003 |
25 pages |
| Authors:
William A. Hargus; John H. Schilling; Quinten E. Walker; Mark A. Cappelli; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE
|
| Clustering multiple thrusters has emerged as a favored option for extending Hall effect thruster propulsion to very high powers (100-150 kW) for a variety of Air Force missions. However, there are inherent difficulties in the simultaneous neutralization of several Hall effect thrusters. Chief among these is the issue of unequal current sharing among multiple cathodes. For this reason, it may prove advantageous to use a single, high current neutralizer. Conventional ... |
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| Very Low Frequency (VLF) Remote Sensing of Gravity Waves Generated by the Auroral Electrojet |
14 JAN 2002 |
6 pages |
| Authors:
T. F. Bell; U. S. Inan; M. K. Demirkol; M. W. Chevalier; R. Moore; STANFORD UNIV CA SPACE TELECOMMUNICATIONS AND RADIOSCIENCE LAB
|
| During the period of performance the VLF remote diagnostic technique was applied in order to characterize both the ambient and modified D-region when perturbed by atmospheric gravity waves generated by the auroral electrojet. The characterization involved VLF sub-ionospheric wave phase and amplitude measurements at four sites located in Alaska and four sites located along the east coast of the North American continent. A total often separate propagation paths were monitored. ... |
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| Modeling Nonequilibrium Radiation in High Altitude Plumes |
01 MAR 2001 |
37 pages |
| Authors:
Iain D. Boyd; CORNELL UNIV ITHACA NY DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
|
| This is final report summarizes the research carried out on the development of numerical approaches for simulating the radiation emitted in high-altitude plumes of spacecraft and missiles. In Appendix I, we describe the development of ultra-violet radiation model for the hydroxyl radical that is implemented in a particle-based Monte Carlo approach for simulating the plumes. In Appendix II, we describe a plume radiation calculation for the plume of the ammonia ... |
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| On-Orbit Optical Observations of the ESEX 26kW Ammonia Arcjet |
11 JAN 2001 |
23 pages |
| Authors:
L. K. Johnson; G. G. Spanjers; D. R. Bromaghim; M. W. Dulligan; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST
|
| During the course of eight flight firings of the ESEX 26 kW arcjet in March and April, 1999, optical observations from on-board and ground-based sensors were obtained. Images from the on-board still camera indicate that the nozzle temperature distribution is consistent with arcjet heating models and ground observations. Images of the thruster plume at 656 nm confirm predictions that the luminescent plume in the space environment is more diffuse and ... |
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| Radiometric Analysis from the 26-kW Electric Propulsion Space Experiment (ESEX) Flight |
11 JAN 2001 |
19 pages |
| Authors:
Gg. G. Spanjers; J. H. Schilling; D. R. Bromaghim; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST
|
| The United States Air Force Research Laboratory's Electric Propulsion Space Experiment (ESEX) was launched and operated in early 1999 in order to demonstrate the compatibility and readiness of a 30 kW class ammonia arcjet for satellite propulsion applications. As part of this flight, an array of on-board contamination sensors was used to assess the effect of the arcjet and other environments on the spacecraft. The sensors consisted of microbalances to ... |
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| Refined Orbital Performance Measurements of the Air Force Electric Propulsion Space Experiment (ESEX) Ammonia Arcjet |
11 JAN 2001 |
26 pages |
| Authors:
J. M. Fife; D. R. Bromaghim; D. A. Chart; W. A. Hoskins; C. E. Vaughan; AIR FORCE RESEARCH LAB EDWARDS AFB CA
|
| During the Electric Propulsion Space Experiment (ESEX) mission, eight firings of the 26 kW ammonia arcjet were performed. Data taken from on-board systems, GPS and ground tracking during these firings are used to determine thruster performance. The on-board Servo Accelerometer Assembly (SAA) measured spacecraft acceleration. The mean values of thrust, specific impulse and thrust efficiency are 1.93 +/- 0.06 Newtons, 786.2 +/- 43.0 seconds and 0.267 +/- 0. 021, respectively. ... |
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| Observations of the Effect on Spacecraft Function and Communications by the ESEX 26kW Ammonia Arcjet |
11 JAN 2001 |
43 pages |
| Authors:
M. J. Dulligan; D. R. Bromaghim; J. A. Zimmerman; D. Hardesty; L. K. Johnson; ENGINEERING RESEARCH AND CONSULTING INCEDWARDS AFB CA
|
| Tests designed to detect the influence of operating the Electric Propulsion Space Experiment (ESEX) 26 kW ammonia arcjet on normal spacecraft communications and operations showed. Two on-board antennas sensitive to the 2, 4, 8, and 12 GHz frequencies detected no increase in signal amplitude that is clearly identifiable with arcjet operation. Analysis of the bit-error rate (BER) tests, a sensitive diagnostic for quantitatively measuring the effect of the arcjet plume ... |
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| Nonintrusive Diagnostic Strategies for Arcjet Stream Characterization |
APR 2000 |
37 pages |
| Authors:
Douglas G. Fletcher; NATIONAL AERONAUTICS AND SPACE ADMINISTRATION MOFFETT FIELD CA AMES RESEARCHCENTER
|
| In the previous lecture, the issues related to arcjet flow modeling were introduced, and the limitations of conventional instrumentation in addressing these issues were discussed The general level of understanding of the arcjet flows was seen to preclude the use of arcjets as aerothermodynamic test facilities beyond the current role in aerothermal material testing, despite their long test duration capability. In this section, the focus will be on new developments ... |
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| Space Propulsion Applications of Helium Arcjets |
21 MAR 2000 |
18 pages |
| Authors:
R. P. Welle; AEROSPACE CORP EL SEGUNDO CA LAB OPERATIONS
|
| With currently available space electric power systems, the optimum specific impulse for electrically propelled satellite transfers from low Earth orbit to geosynchronous Earth orbit appears to be in the 1000 to 1200 second range. Arcjets operating with helium as a propellant may be the most efficient electric thruster capable of operating in this specific impulse range. This work reports on a recent set of experiments which ... |
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| Contamination Measurements from the ESEX 26 kW Ammonia Arcjet Flight Experiment |
15 OCT 1999 |
24 pages |
| Authors:
Greg G. Spanjers; J. H. Schilling; S. F. Engelman; D. R. Bromaghim; L. K. Johnson; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST
|
| The United States Air Force Research Laboratory's Electric Propulsion Space Experiment (ESEX) was launched and operated in early 1999 in order to demonstrate the compatibility and readiness of a 30-kW class ammonia arcjet for satellite propulsion applications. As part of this flight, an array of on-board contamination sensors was used to assess the effect of the arcjet and other environments on the spacecraft. The sensors consisted of microbalances to measure ... |
|
| Preliminary Analysis of Contamination Measurements from the ESEX 26 kW Ammonia Arcjet Flight Experiment |
14 OCT 1999 |
23 pages |
| Authors:
G. G. Spanjers; J. H. Schilling; S. F. Engelman; M. J. Dulligan; D. R. Bromaghim; AIR FORCE RESEARCH LAB EDWARDS AFB CA PROPULSION DIRECTORATE WEST
|
| The United States Air Force Research Laboratory's Electric Propulsion Space Experiment (ESEX) was launched and operated in early 1999 in order to demonstrate the compatibility and readiness of a 30-kW class ammonia arcjet for satellite propulsion applications. As part of this flight, an array of on-board contamination sensors was used to assess the effect of the arcjet and other environments on the spacecraft. The sensors consisted of microbalances to measure ... |
|
| Basic Scaling Studies of Electric Thrusters |
12 MAR 1999 |
7 pages |
| Authors:
Manual Martinez-Sanchez; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF AERONAUTICS AND ASTRONAUTICS
|
| The main goal of the work under this Grant was the clarification of the scaling properties of Hall thrusters, with a view to both, miniaturization, and expansion to high power. This goal was pursued through two complementary efforts, one addressing the scaling issues and technological problems associated with miniaturization of classically arranged Hall thrusters, and the other continuing the fundamental physical modeling work on Hall thrusters, which underlies all scaling ... |
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| A Passive Radar for Atmospheric Remote Sensing Using Commercial FM broadcasts |
05 AUG 1998 |
|
| Authors:
John D. Sahr; UNIV OF WASHINGTON SEATTLE DEPT OF ELECTRICAL ENGINEERING
|
 | We are developing a completely passive bistatic radar using commercial FM broadcasts near 100 MHz. By correlating a clean copy of the broadcasts with the weak, delayed scatter at a remote site, we will generate the full range-Doppler profile of ion acoustic turbulence near the auroral electrojets. More precisely we will be calculating the cross ambiguity function of data from two receivers separated by approximately 100 km, intending to detect ... |
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| Fundamental Studies of the Electrode Regions in Arcjet Thrusters |
MAR 98 |
154 pages |
| Authors:
Mark A. Cappelli; STANFORD UNIV CA DEPT OF MECHANICAL ENGINEERING
|
| This research focuses on the understanding of the plasma dynamics in the near node and near-cathode region of arcjets with an emphasis on the development of an extensive database for the validation of arcjet models. During the first year of this research period, the arc cathode interaction was investigated by in-situ spectroscopic imaging and by axial emission spectroscopy, providing measurements of cathode current density, cathode temperature, and near-cathode plasma properties. ... |
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| The Electric Propulsion Space Experiment (ESEX) - A Demonstration of High Power Arcjets for Orbit Transfer Applications |
03 NOV 1997 |
7 pages |
| Authors:
D. R. Bromaghim; R. M. Salasovich; J. R. LeDuc; L. K. Johnson; PHILLIPS LAB EDWARDS AFB CA
|
| The Electric Propulsion Space Experiment (ESEX) is a high power (30 kW) ammonia arcjet space demonstration sponsored by the Propulsion Directorate of the Phillips Laboratory with TRW as the prime contractor. ESEX is one of nine experiments being launched in early 1998 on board the Advanced Research and Global Observation Satellite (ARGOS). ESEX will demonstrate the feasibility of using a high power arcjet for orbit transfer. ESEX is instrumented with ... |
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| The Stability of Arc Attachment in Arcjet Propulsion Devices |
JAN 97 |
93 pages |
| Authors:
Mark A. Cappelli; Benjamin Yuan; STANFORD UNIV CA DEPT OF MECHANICAL ENGINEERING
|
| The design of high current plasma devices such as arcjet thrusters, arc heaters, magnetohydrodynamic generators, and plasma opening switches has in the past been based mostly on empirical methods. In the case of arcjet thrusters, these methodologies have produced a steady, reliable device when operated at low power levels. However, it is desirable to increase the performance and operating range of the arcjet so that they may run more efficiently ... |
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| Flight Diagnostics and Integrated Vehicle Testing of the U.S. Air Force Electric Propulsion Space Experiment (ESEX) |
DEC 96 |
|
| Authors:
R. M. Salasovich; J. R. LeDuc; L. K. Johnson; D. R. Bromaghim; PHILLIPS LAB EDWARDS AFB CA
|
| The Electric Propulsion Space Experiment (ESEX) comprises a 30 kW ammonia arcjet system, onboard diagnostics, and remote observations program. A scientific plan encompassing implementation, operation, and data analysis has been developed. Onboard instruments will provide accurate measurements of spacecraft acceleration, thruster operating characteristics, and radiated thermal loads, and will document arcjet operation through filtered imagery. Instruments will also provide upper limits for spacecraft contamination and communications band electromagnetic interference. The ... |
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| Electric Propulsion Space Experiment (ESEX) Flight Qualification & Operations |
DEC 95 |
|
| Authors:
A. M. Sutton; D. R. Bromaghim; L. K. Johnson; SPARTA INC EDWARDS AFB CA
|
| The Electric Propulsion Space Experiment (ESEX) is one of eight experiments being launched in early 1997 on the Advanced Research and Global Observation Satellite (ARGOS). ESEX has successfully completed flight qualification and is awaiting integration. ESEX will be the first flight of a high power arcjet propulsion subsystem. The arcjet experiment will nominally fire 10 times for a total of 150 minutes. The flight data will include measurements of both ... |
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| Fundamentals of Arcjet Thruster Thermophysics |
SEP 95 |
113 pages |
| Authors:
Rodney L. Burton; Herman Krier; T. W. Megli; S. A. Bufton; N. T. Tiliakos; ILLINOIS UNIV AT URBANA DEPT OF MECHANICAL AND INDUSTRIAL ENGINEERING
|
| This final technical report summarizes the research carried out by our group concerned with arcjet plasma propulsion. Section 1 describes the nonequilibrium plasma model and a detailed formulation for kinetic nonequilibrium. Section II describes experimental measurements in which measurements of electron number density, electron temperature, ion speed ratio and gas velocity are carried out by advanced Langmuir probes. Section III outlines our research with a modified 1-2 kW class arcjet, ... |
|
| Comparative Analysis of Most Powerful Modern Opening Switches and Plasma Flow Switches |
1995 |
31 pages |
| Authors:
Vladislav Mokhov; INSTITUTE OF THEORETICAL AND EXPERIMENTAL PHYSICS MOSCOW (RUSSIA)
|
| This report results from a contract tasking Institute of Experimental Physics as follows: Perform a comparative study of advanced opening switches and plasma flow switches using ID calculations, theoretical analysis and estimations using existing experimental data. |
|
| Development of Hollow Cathode of High Power Middle Pressure Arcjet |
1995 |
61 pages |
| Authors:
Eujeni Vaulin; AVIATSIONNYI TEKHNOLOGICHESKII INSTITUTMOSCOW (USSR)
|
| This report results from a contract tasking Moscow Aviation Institute as follows: Determine integral performances of arcjet devices in nitrogen, ammonia, and their mixtures using hollow cathode devices at low and high current levels, perform short term tests (up to 50 hours) for operational reliability and determination of capabilities. |
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| Low Power Arcjet Performance Evaluation |
1995 |
13 pages |
| Authors:
Keith A. McFall; Dennis L. Tilley; Frank S. Gulczinski III; PHILLIPS LAB EDWARDS AFB CA
|
| The use of electric propulsion for stationkeeping and orbit repositioning missions offers significant' advantages to Air Force users. Commercial interest in electric propulsion has largely focused on geostationary north-south stationkeeping of high power communication satellites. and has resulted in the development and flight qualification of several thruster types operating in the 1500-2000 W power range. Since the power available for propulsion on many current and future Air Force satellites is ... |
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| Laser Induced Fluorescence of Ground State Hydrogen Atoms in an Arcjet Plume |
1995 |
12 pages |
| Authors:
Jeffrey A. Pobst; Ingrid J. Wysong; Ronald A. Spores; PHILLIPS LAB EDWARDS AFB CA
|
| We report two photon laser induced fluorescence measurements near the nozzle exit and in the plume of a 1 kW arcjet thruster. Atomic hydrogen number densities, axial and radial velocities, and translational temperatures are measured in the expansion plume of a 1 kW arcjet operating on hydrogen propellant. Data from recent computational models are compared with the atomic hydrogen density measurements. |
|
| Development of Cathodic Materials for Arcjet Devices |
1995 |
34 pages |
| Authors:
Gennady Burkhanov; RUSSIAN ACADEMY OF SCIENCES MOSCOW INST OF PHYSICAL CHEMISTRY
|
| This report results from a contract tasking Russian Academy of Sciences as follows: Procure materials for and manufacture samples of cathode materials for long life application in arc jet thruster systems. |
|
| CVD Diamond Cost Analysis Update |
94 |
4 pages |
| Authors:
IBIS ASSOCIATES INC WELLESLEY MA
|
| Progress for IBIS Associates in the fourth quarter of 1994 includes discussion with 3M and Research Triangle Institute regarding their radio frequency (RF) CVD diamond deposition technology. Although modeling this technology has not been accomplished, the non-disclosure agreements have been taken care of. IBIS awaits feedback on the schedules of 3M and RTI contacts for modeling to proceed. Also accomplished in the fourth quarter of 1994 was initial discussion with ... |
|
| CDAW-9 Analysis of Magnetospheric Events on 3 May 1986: Event C |
01 OCT 93 |
64 pages |
| Authors:
D. N. Baker; T. I. Pulkkinen; R. L. McPherron; J. D. Craven; L. A. Frank; AEROSPACE CORP EL SEGUNDO CA ENGINEERING AND TECHNOLOGY GROUP
|
| The ninth Coordinated Data Analysis Workshop (CDAW-9) focussed upon several intervals within the PROMIS period (March-June 1986). Event interval C comprised the period 0000-1200 UT on 3 May 1986 which was a highly disturbed time near the end of a geomagnetic storm interval. A very large substorm early in the period commenced at 0111 UT and had a peak AE index value of approx. 1500 nT. Subsequent activity was lower, ... |
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| The Major Magnetic Storm of March 13-14, 1989 and Associated Ionosphere Effects |
30 JUN 1993 |
17 pages |
| Authors:
F. J. Rich; W. F. Denig; PHILLIPS LAB HANSCOM AFB MA
|
| The geomagnetic storm of March 1989 was the largest geomagnetic storm of the decade and one of the largest of the century. We review many of the 'high-latitude' ionospheric observations that were made during this storm. Most of the data presented here comes from the polar-orbiting satellites of the Defense Meteorological Satellite Program (DMSP) series. A review of the DMSP data shows that most of the high-latitude, top-side ionospheric disturbance ... |
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| ELF/VLF/LF Radio Propagation and Systems Aspects (La Propagation des Ondes Radio ELF/VLF/LF et les Aspects Systemes) |
MAY 93 |
|
| Authors:
ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT NEUILLY-SUR-SEINE (FRAN CE)
|
| This publication reports the papers presented to a specialists' meeting held by the Electromagnetic Wave Propagation Panel at its Fall 1992 meeting. The topics covered on the occasion of that symposium include: Propagation aspects; Numerical modelling; Propagation measurements; and Propagation in sea water. Radio noise and interference; Long wave TE/TM Noise prediction model; Measurements; and ELF generated by auroral electrojet modulation. Antenna considerations; Antenna fundamentals; Scale modelling; Measurements of pattern ... |
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| Auroral-E Observations: The First Year's Data |
FEB 93 |
73 pages |
| Authors:
R. B. Rose; R. D. Hunsucker; NAVAL COMMAND CONTROL AND OCEAN SURVEILLANCE CENTER RDT AND E DIV SAN DIEGO CA
|
| Personnel at the Naval Command, Control and Ocean Surveillance Center, RDT and E Division, and RP Consultants conducted a year-long study to measure and characterize auroral-E propagation. Personnel installed a 100-watt transmitter at the Arctic Submarine Laboratory at Cape Prince of Wales (67 N, 168 W) and a receiver at RP Consultants' facilities 900 kilometers away. Both sites used simple dipole antennas. The transmitter sent a slow morse R on ... |
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| Arcjet Thruster Experimental Facility at the United States Air Force Phillips Laboratory |
SEP 1992 |
8 pages |
| Authors:
A. M. Sutton; S. Castillo; PHILLIPS LAB EDWARDS AFB CA
|
| The paper discusses the unique design and construction of the vacuum, cooling, power and propellant systems of the arcjet experimental facility. An overview of current and future arcjet thruster development is presented. The thrusters discussed are 10-30 kilowatts in power, use ammonia or hydrogen as propellant, and are either radiation cooled or regeneratively cooled. Extensive calibrations have been conducted on the mass flow system. The uncertainties have been quantified over ... |
|
| Electrojet Modulation ELF Communications, |
OCT 1990 |
|
| Authors:
K. Papadopoulos; R. A. Shanny; L. Susman; M. Machina; P. Stamboulis; ARCO POWER TECHNOLOGIES INC WASHINGTON DC
|
| Me causes for the inefficient conversion of HF to ELF waves by ionospheric heating observe in recent experiments are examined. It is found that for the low frequency HF range 2.5-4 MHz used in the present experiments the modified conductance saturates during a fraction of the HF irradiation cycle. As a result most of the HF energy is transferred to processes that do not affect the conductance significantly. This was ... |
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| Oblique Heating of the Auroral Ionosphere by LF/MF Transmitters, |
OCT 1990 |
|
| Authors:
P. S. Cannon; M. J. Rycroft; T. Turunen; ROYAL AEROSPACE ESTABLISHMENT FARNBOROUGH (UNITED KINGDOM)
|
| The paper describes the generation of ELF signals due to oblique heating of the auroral ionosphere by signals from ELF modulated LF/MF radio transmitters. Apart from signals of natural origin, timing signals (six pips which occurred on the hour) were received. The pips of frequency 1 kHz, duration 1 05 ms and field strength -0.1 pT exhibit a favoured source location -1 50 km south-southeast of Sodankyla. The pips are ... |
|
| Effects of Energy, Momentum and Particle Transport in the Near-Earth Solar Terrestrial System |
01 JUN 90 |
83 pages |
| Authors:
P. B. Anderson; E. M. Basinska-Lewin; M. E. Greenspan; J. H. James; D. R. Weimer; REGIS COLL RESEARCH CENTER WESTON MA
|
| This work has included the scientific studies of high-latitude plasma irregularities and the physics of the aurora, engineering of space environmental sensors, and dat processing services. Scientific studies were conducted in the areas of energy dissipation, magnetosphere-ionosphere interactions and ionospheric plasma. Design work has been done on a series of plasma instruments for the Defense Meteorological Satellite Program (DMSP), the Combined Release and Radiation Effects Studies (CRRES), the Photovoltaic Array ... |
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| Goose Bay Radar Observations of Earth-Reflected Atmospheric Gravity Waves in the High-Latitude Ionosphere, |
03 MAY 1990 |
|
| Authors:
J. M. Ruohoniemi; R. A. Greenwald; K. B. Baker; J. C. Samson; JOHNS HOPKINS UNIV LAUREL MD APPLIED PHYSICS LAB
|
| An HF backscatter radar at Goose Bay, Labrador made it possible to observe irregularities in the distribution of ionospheric ionization at E and F region altitudes (100 - 600 km) in the high-latitude (65 - 85 deg Lambda) ionosphere. Recently it has been established that the passage of atmospheric gravity waves perturbs the ionosphere in ways that are readily detected in returns that reflect off the ionospheric layers. The particular ... |
|
| Estimation of Ionospheric Electrodynamic Parameters Using Ionospheric Conductance Deduced from Bremsstrahlung X-Ray Image Data |
16 FEB 89 |
56 pages |
| Authors:
B.-h. Ahn; H. W. Kroehl; Y. Kamide; D. J. Gorney; AEROSPACE CORP EL SEGUNDO CA SPACE SCIENCES LAB
|
| Various ionospheric electrodynamic parameters are calculated by using ground magnetic records from a total of 88 stations in the northern hemisphere. For this purpose, an instantaneous conductance distribution deduced from the DMSP-F6 bremsstrahlung X-ray image data is utilized. It is a unique opportunity to examine some of the inherent ambiguity in the magnetogram-inversion technique based on a statistically-derived conductance model. Important conclusions are: (1) The pole-ward portion of the westward ... |
|
| Final Report for The Pennsylvania State University Communications and Space Sciences Laboratory Contract N00014-86-K-0677 |
89 |
175 pages |
| Authors:
A. J. Ferraro; Alfred W. Wong; PENNSYLVANIA STATE UNIV UNIVERSITY PARK COMMUNICATIONS AND SPACE SCIENCES LAB
|
| The broad research objective of this program has been to investigate unique concepts for generating ULF, ELF, and VLF using the ionosphere as the wireless antenna. The wireless Antenna or HF demodulation experiment was demonstrated in 1980 using the Arecibo observatory's heating facility. Modulation of the dynamo current system at that latitude was the major source for the wireless antenna. Some of the major experimental accomplishments are: Excellent quality of ... |
|
| Proceedings of a Symposium on Perspectives in Fluid Mechanics Held in Pasadena, California on 10-12 January 1985 |
29 JUL 88 |
216 pages |
| Authors:
Donald Coles; CALIFORNIA INST OF TECH PASADENA
|
| Contents: Methods for Exploring the Large-Scale Ocean Turbulence; Astrophysical Jets; Natural and Artificial Flying Machines; The Role of Cartoons in Turbulence; Early Transonic Ideas in the Light of Later Developments; Perspectives in Vortex Dynamics; Dynamical System Theory and Simple Fluid Flow; Turbulence Research by Numerical Simulation; and Geologic nozzles. (JHD) |
|
| Antarctic Atmospheric Infrasound |
NOV 86 |
|
| Authors:
Charles R. Wilson; Bruce N. McKibben; ALASKA UNIV FAIRBANKS GEOPHYSICAL INST
|
| In order to monitor atmospheric infrasonic waves in the passband from 0.1 to 0.01 Hz a digital infrasonic detection system was installed in Antarctica on the Ross Ice shelf near McMurdo Station on McMurdo Sound. An array of seven infrasonic microphones subtending an area of about 35 sg km was operated in Windless Bight. The analog microphone data was telemetered to McMurdo station where the infrasonic date were digitized and ... |
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| The Global Auroral Responses to Magnetospheric Compressions by Shocks in the Solar Wind: Two Case Studies |
APR 85 |
|
| Authors:
J. D. Craven; L. A. Frank; C. T. Russell; E. J. Smith; R. P. Lepping; IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY
|
| Two case studies are presented of the global auroral responses to shocks in the solar wind at Earth. The z component of the interplanetary magnetic field, Bz, is negative ahead and behind the first shock and positive for the second case. A sudden-commencement geomagnetic storm develops in each case, with maximum D sub st somewhat 0, appearing first at local midnight as a polar arc and then lengthening sunward from ... |
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| High-Latitude Ionospheric Irregularities |
10 MAY 1984 |
|
| Authors:
J. F. Vickrey; R. C. Livingston; R. M. Robinson; N. B. Walker; SRI INTERNATIONAL MENLO PARK CA
|
| This document summarizes studies on the morphology of ionospheric structure at high latitudes. The program encompasses both theoretical and experimental investigations into this rapidly developing field. Because of the vast range of scale sizes (hundreds of kilometers to centimeters) that make up the structure, and the need for time-continuous observations, we employ a diverse set of observational techniques. These include in situ observations from rockets and satellites as well as ... |
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| Short Wavelength Stabilization of the Gradient Drift Instability due to Velocity Shear |
04 MAY 1983 |
|
| Authors:
J. D. Huba; L. C. Lee; NAVAL RESEARCH LAB WASHINGTON DC
|
| A nonlocal analysis of the gradient drift instability is presented. The new effect included in this theory is the allowance for an inhomogeneous electric field which produces a sheared drift velocity. It is found that velocity shear can stabilize the short wavelength modes of the instability, and preferentially excite a longer wavelength mode than would be expected based upon local theory. This result may explain the observations of dominant, long ... |
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| Medium, Long and Very Long Wave Propagation (at Frequencies Less than 3000 kHz) |
FEB 1982 |
|
| Authors:
J. S. Belrose; ADVISORY GROUP FOR AEROSPACE RESEARCH AND DEVELOPMENT NEUILLY-SUR-SEINE (FRANCE)
|
| These Proceedings include the papers and discussions presented at the AGARD Electromagnetic Wave Propagation Panel Symposium on 'Medium, Long and Very Long Wave Propagation (at Frequencies less than 3000 kHz)' held in Brussels, Belgium in September 1981. The Meeting reviewed propagation information at ELF and VLF frequencies. It was intended to summarize the current state of knowledge in this frequency band in the areas of propagation, antennas, and radio communications ... |
|
| Atmospheric Pressure and Velocity Fluctuations Near the Auroral Electrojet |
15 JAN 1982 |
|
| Authors:
Janet G. Luhmann; AEROSPACE CORP EL SEGUNDO CA SPACE SCIENCES LAB
|
| The low frequency pressure and velocity perturbations caused by the temporally varying Lorentz force associated with auroral electrojet activity are modelled by calculating the disturbances generated by a two-dimensional, time- dependent current system in a gravitationally stratified, isothermal, windless atmosphere. These calculations provide information about the pattern of gravity waves around the hypothetical electrojet and give estimates of the magnitudes of near-field auroral disturbances in the middle atmosphere. It is ... |
|
| Modeling of High-Latitude Currents in a Substorm |
11 DEC 1981 |
|
| Authors:
J. L. Karty; C. -k. Chen; R. A. Wolf; M. Harel; R. W. Spiro; RICE UNIV HOUSTON TX
|
| A quantitative model is developed for computing currents and electric fields in the area covered by the poleward set of field-aligned currents (region-1 Birkeland currents). The high-latitude band considered carries most of the westward electrojet and lies just poleward of the region treated in the Rice University computer simulation (which covers the inner magnetosphere and corresponding ionosphere); the present high-latitude-current model supplements the inner-magnetosphere simulations to make them nearly global. ... |
|
| Analysis of Data for the Development of Density and Composition Models of the Upper Atmosphere |
JUL 1981 |
|
| Authors:
Luigi G. Jacchia; Jack W. Slowey; SMITHSONIAN ASTROPHYSICAL OBSERVATORY CAMBRIDGE MA
|
| This work was directed toward the ultimate goal of developing an improved model of the temperature, density, and composition of that region of the earth's neutral atmosphere above the turbopause. A wealth of data has become available, mainly in the form of total density and composition from satellite- borne mass-spectrometers, in recent years. Most of the work performed under the contract consisted of the analysis of data from the ESRO ... |
|
| The Mesosphere and Thermosphere |
1981 |
|
| Authors:
K. S. W. Champion; G. Schmidtke; AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA
|
| This publication contains a number of specialized papers on two topics. The first topic is representation of energy sources in the Earth's upper atmosphere and ionosphere. The energy sources include the solar wind and electromagnetic radiation, particle precipitation, joule heating in the electrojets, and energy transfer by gravity wave dissipation. The second topic is concerned with models of the terrestrial upper atmosphere. The subdivisions include the stratosphere, mesosphere, thermosphere and ... |
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| Simultaneous Observations of Auroral Zone Electrodynamics by Two Satellites: Evidence for Height variations in the Topside Ionosphere |
10 NOV 1980 |
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| Authors:
Frederick J. Rich; Cynthia A. Cattell; Michael C. Kelley; William J. Burke; AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA
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| The S3-2 and S3-3 satellites were launched with identical orbit inclinations and with apogees of 1500 and 8000 km respectively. Both satellites were equipped to measure magnetic fields, electric fields, and energetic electrons. By comparing a few cases when the satellites were crossing the auroral zone at approximately the same universal time and location, altitude variations in the electrodynamics of the auroral zone can be separated from universal and local ... |
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| Recent Computational Studies of the Equatorial Electrojet. |
24 MAR 1980 |
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| Authors:
M. J. Keskinen; NAVAL RESEARCH LAB WASHINGTON DC
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| A brief review of recent computational studies of the E-region equatorial electrojet is presented. Agreement and discrepancies between numerical simulation studies and both theory and experiment are given. Some outstanding problems are identified and new experiments suggested. |
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| A Correlation between Auroral Kilometric Radiation and Field-Aligned Currents. |
MAY 1979 |
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| Authors:
James Lauer Green ; Nicolaos A. Saflekos ; Donald A. Gurnett ; Thomas A. Potemra; IOWA UNIV IOWA CITY DEPT OF PHYSICS AND ASTRONOMY
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| Simultaneous observations of field-aligned currents (FAC) and auroral kilometric radiation (AKR) are compared from the polar orbiting satellites Triad and Hawkeye. The Triad observations were restricted to the evening-to-midnight local time sector (19 to 01 hours magnetic local time) in the northern hemisphere. This is the region where it is believed the most intense storms of AKR originate. The Hawkeye observations were restricted to when the satellite was in the ... |
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Reports by Keyword(s)
ELECTROJETS
