These proceedings are based upon introductory talks, research reports and discussions from the NATO Advanced Workshop on the "Morphology and Dynamics of the Polar Cusp", held at Lillehammer, Norway, 7-12 May, 1984. The upper atmosphere at high latitudes is called the "Earth's win dow to outer space". Through various electrodynamic coupling process es as well as through direct transfer of particles many geophysical effects displayed there are direct manifestations of phenomena occurring in the deep space. The high latitude ionosphere will also exert a feedback on the regions of the magnetosphere and atmosphere to which it is coupled, acting as a momentum and energy source and sink, and a source of particles. Of particular interest are the sections of the near space known as the Polar Cusp. A vast portion of the earth's magnetic field envelope is electrically connected to these regions. This geometry results in a spatial mapping of the magnetospheric pro cesses and a focusing on to the ionosphere. In the Polar Cusps the solar wind plasma has also direct access to the upper atmosphere. The polar regions are thus of extreme importance when it comes to under standing the physical processes in the near space and their effect on our environment. The Introductory Talks given at this workshop provided a common background for discussing and understanding the physics of the Polar Cusp. By this book we will make the information which thus was provid ed to the participants of the workshop accessible to a wider audience.

"Reprinted from Surveys in geophysics, volume 26 (1-3), 2005."

Proceedings of the NATO Advanced Research Workshop, Lillehammer, Norway, September 20-24, 1988

Überblick über den aktuellen Wissensstand und künftige Forschungsrichtungen in der Magnetosphärenphysik In den sechs Jahrzehnten seit der Einführung des Begriffs ?Magnetosphäre? sind über den magnetisierten Raum, der jeden Körper in unserem Sonnensystem umgibt, viele Theorien entstanden und viele Erkenntnisse gewonnen worden. Jede Magnetosphäre ist einzigartig und verhält sich doch entsprechend den universellen physikalischen Vorgängen. Der Band ?Magnetospheres in the Solar System? enthält Beiträge von Experten für Experimentalphysik, theoretische Physik und numerische Modellierung, die einen Überblick über verschiedene Magnetosphären vermitteln, von der winzigen Magnetosphäre des Merkur bis zu den gewaltigen planetarischen Magnetosphären von Jupiter und Saturn. Das Werk bietet insbesondere: * Einen kompakten Überblick über die Geschichte der Magnetosphäre, ihre Grundsätze und Gleichungen * Eine Zusammenfassung der grundlegenden Prozesse in der Magnetospährenphysik * Instrumente und Techniken zur Untersuchung von Prozessen in der Magnetosphäre * Eine besondere Schwerpunktsetzung auf die Magnetosphäre der Erde und ihre Dynamik * Eine Darstellung der planetaren Magnetfelder und Magnetosphären im gesamten Sonnensystem * Eine Definition der künftigen Forschungsrichtungen in der Magnetosphärenphysik Die Amerikanische Geophysikalische Vereinigung fördert die wissenschaftliche Erforschung der Erde und des Weltraums zum Wohle der Menschheit. In ihren Publikationen werden wissenschaftliche Erkenntnisse veröffentlicht, die Forschern, Studenten und Fachkräften zur Verfügung stehen.

The Los Alamos Chapman Conference on Magnetospheric Substorms and Related Plasma Processes can be considered the fourth in a series devoted to magnetospheric substorms, after the Moscow (1971), Houston (1972), and Bryce Mountain (1974) meetings. The main motivation for organizing the Los Alamos Conference was that magnetospheric substorm studies have advanced enough to the point of bringing experimenters, analysts and theorists together to discuss major substorm problems with special emphasis on theoretical interpretations in terms of plasma processes. In spite of an extremely heavy schedule from 8:30 A.M. to 10:00 P.M., every session was conducted in an enjoyable and spirited atmosphere. In fact, during one of the afternoons that we had put aside for relaxation, John Winckler led a group of the attendees in a climb to the ceremonial cave of a prehistoric Indian ruin at Bandelier National Monument, near Los Alamos under a crystal blue sky and a bright New Mexico sun. There, they danced as the former dwellers of the pueblo had, perhaps as an impromptu evocation of a magnetospheric event.

Nobel symposium No. 54 on High Latitude Magnetospheric/Iono spheric Plasma Physics was organized in Kiruna, Sweden on March 22-25, 1982 by Kiruna Geophysical Institute and EISCAT Scientific Association. Some 50 leading experts from Western Europe, America and USSR were invited to the Symposium. One main purpose of the Symposium was to prepare for the intense European research effort in space plasma physics in the middle 1980's, in which the EISCAT facilities and the Swedish satellite Viking are two of the more important constituents. The prograuune of the symposium was tied to the physics of those regions of near space where EISCAT and Viking are expected to pro vide important new observational results. This is rather well covered by the t it Ie of these proceedings: High Lat itude Space Plasma Physics. The first two sessions dealt with the physics of the high latitude ionosphere and the third one with how this part of near space is affected by the properties of the solar wind and the interplanetary magnetic field. The remaining three sessions covered fairly extensively the high latitude magnetospheric physics at altitudes of 1-2 earth radii, which is the main scien tific object of the Viking project. The Prograuune COllDlittee of the Kiruna Nobel Symposium was composed of the following European scientists: P. Bauer (Issy-les-Moulineaux), R. Bostrom (Uppsala), C.G. FalthallDlar (Stockholm), T. Hagfors (Kiruna, Cochairman), o. Holt (Troms, s), B. Hultqvist (Kiruna, Cochairman), H. Kohl (Lindau), J. Oksman (Oulu), H. Rishbeth (Chilton), and L. Stenflo (Ume!).

The 6th ESLAB Symposium, organised by the Space Science Department (formerly ESLAB) of the European Space Research and Technology Center, was held in Noord wijk from 26-29 September 1972. This year the theme was "Photon and Particle Interactions with Surfaces in Space". More than 60 scientists attended mainly from ESRO Member States and from America. The first part of the Symposium was devoted to introductory lectures and to papers on interactions with spacecraft. The second half dealt with the photon and particle interactions with celestial objects, and ended with a general discussion and presenta tions of areas where new developments are required. The purpose of this Symposium was to throw light on the importance of the prob lems which are evoked by E. A. Trendelenburg in his introductory remarks, and to sum up our present understanding of these phenomena. It is hoped that this book will prove useful to physicists and engineers who are actually involved in space ex periments and are concerned with interactions of these types. R. J. L. GRARD OPENING ADDRESS Gentlemen, I should like to welcome you to the 6th ESLAB Symposium. In the past we have always organised this Symposium jointly with our sister in stitute, ESRIN, in Frascati, but unfortunately reductions in the scientific budget have forced ESRO to terminate the activities of that laboratory. Nevertheless, we have decided to carryon the tradition, and we shall continue on our own organising this series of symposia on specialised subjects.

The 1969 ESLAB symposium 'Intercorrelated Satellite Observations Related to Solar Events' was held at a time when the importance of bringing together measure ments made simultaneously in different regions of space was beginning to be appreciated. To-day it is universally accepted that the major experimental steps forward in understanding the physics of the Sun-Earth relationships are likely to be made through pre-planned correlated satellite studies. Such considerations have led to the organisation of the International Magnetospheric Study and the joint ESROj NASA International Magnetospheric Explorer, (Mother-Daughter-Heliocentric) mission. The seventh ESLAB symposium was planned as a follow up to that of 1969 with the aim of deriving maximum benefit from those spacecraft which through good fortune found themselves simultaneously operating in different regions of the magnetosphere and interplanetary space. ESRO had launched in early 1972 its HEOS-2 satellite to investigate fields and particles in the unexplored region far above the North pole of the Earth and it became clear that the interesting new results arriving from that mission could profitably be linked with those from various American and the U.S.S.R. PROGNOZ satellites. The book follows the order of the symposium (unfortunately the PROGNOZ contribution did not materialise) concentrating, through both review lectures and of new experimental results, on the nature of the boundaries between the presentation the interplanetary medium and the magnetosphere and the interaction of each region on the other.

The Arctic region is the keystone to understanding the present status ofcurrently ongoing Earth systems and to predicting future imagesof our planet as viewed from northern high latitudes. The Arctic region,composed of ice-covered Arctic ocean in its center and surroundingfragmentation of the major continents, has been investigatedduring the last half century through all kinds of scientific studies:bioscience, physical sciences, geoscience, oceanography, and environmental studies, together with the technological domain. This book covers topics on the recent developments of all kinds of scientific research in and around the Arctic region, with a view to monitoring the current variations in the extreme environment, affected by remarkable changes in temperature and sea-ice extent, mass loss of ice-sheet and glaciers, and variations in marine and terrestrial ecosystems, including human activities.