摘要:

The Dynamics Explorer (DE) program summarizes its accomplishments during the first 5 years since the launch of the two DE satellites. This introduction to six review articles provides background information and a brief history of the program, especially citing the contributions of many people to its development. The principal investigators who had primary responsibility to implement the program are listed, together with the instruments they provided. Orbital information and approaches and constraints to data acquisition are explained. The brief description of the ground data processing and analysis system provides information on access to data catalogs and data sets. Each review article is then placed in the context of the categories of scientific objectives of the program.

ISSN:8755-1209    

DOI:10.1029/RG026i002p00209

年代:1988

数据来源: WILEY

摘要:

The suprathermal plasma instruments on DE 1 and DE 2 (high‐altitude plasma instrument, low‐altitude plasma instrument, and energetic ion composition spectrometer) have provided new data on the distribution functions and composition of plasmas at altitudes from a few hundred to ∼23,000 km. Of particular interest are the results that have been obtained on the injection and transport of plasma in the polar cusp, on the upward acceleration of ionospheric ions and electrons, and on the charge carriers of the various high‐latitude Birkeland current systems (using independent measurements of the currents by the magnetic field instruments MAG‐A and MAG‐B). These results and other contributions of the Dynamics Explorer hot plasma and magnetic field measurements to our understanding of magnetosphere‐ionosphere coupling are reviewed

ISSN:8755-1209    

DOI:10.1029/RG026i002p00215

年代:1988

数据来源: WILEY

摘要:

The geospace environment has been viewed as a mixing bowl for plasmas of both solar and terrestrial origin. Our perspective on the nature of the supply mechanisms has undergone a radical evolution over the past decade, particularly during the 5 years of the Dynamics Explorer mission. During this period, the terrestrial source has increased in importance in both magnitude and character of ionospheric outflow. These outflows include the classical polar wind, the cleft ion fountain, the auroral ion fountain, and the polar cap. The Earth can be envisioned as a multifaceted fountain which ejects particles from different spatial locations spread around the globe. These particles exhibit a range of masses from 1 to 32 amu and a range of energies from 1 eV to 10 keV. The total flux of this ionospheric outflow is very large: adequate to supply the entire magnetospheric particle population. And the implications of the outflow are significant across a broad spectrum of solar‐terrestrial processes ranging from sources of magnetospheric plasmas, to influences on ionospheric density and temperature structure, to energy transfer in phenomena such as stable auroral red arcs. The Dynamics Explorer mission has made a major contribution in the characterization of the terrestrial plasma sourc

ISSN:8755-1209    

DOI:10.1029/RG026i002p00229

年代:1988

数据来源: WILEY

摘要:

We provide an overview of several of the most significant results from the global imaging instrumentation on board the Earth‐orbiting spacecraft Dynamics Explorer 1. These topics include (1) the evolution of the auroral oval during substorms, (2) fluctuations of polar cap area encircled by the auroral oval during a magnetic substorm, (3) the mapping of poleward arcs of the auroral oval into the plasma sheet boundary layer, (4) the theta aurora, (5) atmospheric holes, (6) the geocorona, and (7) the rates of water loss from comet Halle

ISSN:8755-1209    

DOI:10.1029/RG026i002p00249

年代:1988

数据来源: WILEY

摘要:

This paper reviews the results from the plasma wave instrument on the Dynamics Explorer 1 (DE 1) spacecraft. The DE 1 spacecraft was launched on August 3, 1981, into an elliptical polar orbit with initial perigee and apogee radial distances of 1.09 and 4.65RE. In the roughly 6 years since the launch of the spacecraft, DE 1 has provided basic new information on a wide variety of magnetospheric plasma wave phenomena. These include auroral kilometric radiation, auroral hiss,Zmode radiation, narrow‐band electromagnetic emissions associated with equatorial upper hybrid waves, whistler mode emissions, wave‐particle interactions stimulated by ground VLF transmitters, equatorial ion cyclotron emissions, ion Bernstein mode emissions, and electric field turbulence along the auroral field lines. We first give a brief review of the basic plasma wave modes that can exist in the equatorial and polar regions of the magnetosphere. After the basic terminology is established, each of the above areas of plasma wave research is discussed in detail, first by reviewing the state of knowledge at the time of the DE 1 launch and then by describing the contribution made by DE 1 in the 6 years since the spacecraft was launc

ISSN:8755-1209    

DOI:10.1029/RG026i002p00285

年代:1988

数据来源: WILEY

摘要:

A brief description of the contributions of the Dynamics Explorer (DE) program to an understanding of ionospheric plasma dynamics is given. In addition to being used in some further study of small‐scale structure in the equatorial ionospheric number density, the DE 2 intrumentation has been extensively used to study the bulk motion of the plasma in the equatorial ionosphere. Variations in the east‐west plasma drift, at night as a function of magnetic flux tube apex height, show a decrease in magnitude with increasing height above the altitude of the peakFregion concentration. The role of bothEregion andFregion winds in producing this behavior and the differences between DE measurements taken at solar maximum and similar observations at solar minimum have been discussed. The work described here shows a general convergence of opinion about the behavior of the ionospheric convection pattern at high latitudes during periods of southward interplanetary magnetic field (IMF). Progress has been made in describing the magnetosphere‐solar wind interaction that may be involved in the production of the convection pattern. In particular, the expected magnetic field topology and the applicability of different convection drivers have been examined. The characteristics of the high‐latitude ionospheric plasma motion during periods of northward IMF have been extensively studied. Under such conditions the existence of small‐scale (1–10 km) and medium‐scale (10–200 km) structures in the electric field and plasma motion is quite evident. Its relationship to auroral forms and in particular to the theta aurora has been examined in some detail. The interpretation of larger‐scale electric field and plasma drift features in terms of closed loop convection trajectories and the applicability of different theoretical models to the data have al

ISSN:8755-1209    

DOI:10.1029/RG026i002p00317

年代:1988

数据来源: WILEY

摘要:

Instrumentation flown on the Dynamics Explorer 2 (DE 2) spacecraft enabled the dynamics of both the neutral and the ionized components of the Earth's upper atmosphere to be monitored over the lifetime of the spacecraft, from August 1981 to February 1983. The direct measurements of global thermospheric vector neutral winds and ion drifts were supplemented by observations of neutral and ionic constituent abundances and temperatures, precipitating particle fluxes and pitch angle distributions, electric and magnetic fields, and global‐scale auroral luminosity distributions. Analysis of this unique and comprehensive global data base has led to advances in our understanding of the manner in which the Earth's thermosphere responds dynamically to the insertion of energy and momentum. We review the scientific progress achieved over the past 5 years through the efforts of members of the Dynamics Explorer science team and the other interested scientists who have used the DE data base to investigate the dynamical response of the thermospher

ISSN:8755-1209    

DOI:10.1029/RG026i002p00329

年代:1988

数据来源: WILEY