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

These proceedings are based on the invited talks and selected research reports presented at the NATO Advanced Study Institute (ASI) on "POLAR CAP BOUNDARY PHENOMENA" held at Longyearbyen, Svalbard, June 4 - 13, 1997. The role of the polar cap and its boundary is very substantial in solar-terrestrial physics. At this NATO AS! a major change in thinking on the "cusp" precipitation region in the high-latitude days ide upper atmosphere was reflected, at least for intervals when the interplanetary magnetic field (IMF) is directed southward. It is likely that this has implications for northward IMF as well. The change comes from the now almost complete acceptance of the concept of magnetosheath particle entry along open magnetic field lines and the evolution of the precipitation into the upper atmosphere with time elapsed since magnetic reconnection which opened the field line. A key prediction of this view is that the low-latitude boundary layer (LLBL) is on open field lines.

Summary of the NATO Advanced Research Workshop on Physical Signatures of Magnetospheric Boundary Layer Processes T A POTEMRA, M I PUDOVKIN, R W SMITH, V M VASYLIUNAS and A EGELAND 451 PREFACE These proceedings are based on the invited talks and selected research reports presented at the NATO Advanced Workshop on "PHYSICAL SIGNATURES OF MAGNETOSPHERIC BOUNDARY LAYER PROCESSES", held at Sundvolden Hotel, Norway, 9.-14.May 1993. The international political and scientific communities have gradually realized that the Earth's environment is more fragile than previously believed. This has led to the establishment of international research programmes directed toward the understanding of "Global Change". The Earth's magnetosphere, "the Earth-space", is a part of our environment, and physical processes in the magnetosphere and coupling between the solar energy stream, the solar wind, and the Earth-space are important in the complete understanding of our environment. Variations in the electromagnetic and particle energy output of the Sun have a significant effect on global changes. The energy transfer mechanisms at the days ide magnetospheric boundary layers and their ionospheric signatures are perhaps even more important to solar terrestrial research than the night-side processes in this connection. The dayside boundary layers and the polar cusps are the Earth's windows to outer space. The present NATO ARW was the latest in a series of conferences focused on dayside magnetospheric phenomena. It is five years since the preceding Workshop on "Electromag netic Coupling in the Polar Clefts and Caps" was held at Lillehammer in September 1988.

The participation of such diverse scientific and technical disciplines as meteorology, astronomy, atmospheric electricity, ionospheric and magnetospheric physics, electromagnetic wave propagation, and radio techniques in the research of atmospherics means that results are published in scientific papers widely spread throughout the literature. This Handbook collects the latest knowledge on atmospherics and presents it in two volumes. Each chapter is written by an expert in his or her field. Topics include the physics of thunderclouds, thunder, global atmospheric electric currents, biological aspects of sferics, and various space techniques for detecting lightning within our own atmosphere as well as in the atmospheres of other planets. Up-to-date applications and methodology are detailed. Volumes I and II offer a comprehensive discussion that together will serve as an important resource for practitioners, professionals, and students alike.

All aspects of space plasmas in the Solar System are introduced and explored in this text for senior undergraduate and graduate students. Introduction to Space Physics provides a broad, yet selective, treatment of the complex interactions of the ionized gases of the solar terrestrial environment. The book includes extensive discussion of the Sun and solar wind, the magnetized and unmagnetized planets, and the fundamental processes of space plasmas including shocks, plasma waves, ULF waves, wave particle interactions, and auroral processes. The text devotes particular attention to space plasma observations and integrates these with phenomenological and theoretical interpretations. Highly coordinated chapters, written by experts in their fields, combine to provide a comprehensive introduction to space physics. Based on an advanced undergraduate and graduate course presented in the Department of Earth and Space Sciences at the University of California, Los Angeles, the text will be valuable to both students and professionals in the field.

Perturbation electric and magnetic fields carry in excess of 10(exp10) to 10(exp12) W of electrical power between the magnetosphere and high-latitude ionosphere. Most of this power is generated by the solar wind. The ionosphere at large spatial and temporal scales acts as a dissipative slab which can be characterized by its height-integrated Pedersen conductivity sigma p, so that the power flux into the ionosphere due to a quasi-static electric field E is given by sigma (pE2) The energy transferred to the ionosphere by time-varying electromagnetic fields in the form of Alfven waves is more difficult to calculate because density and conductivity gradients can reflect energy. Thus, field resonances and standing wave patterns affect the magnitude and altitude distribution of electrical energy dissipation. We use a numerical model to calculate the frequency-dependent electric field reflection coefficient of the ionosphere and show that the ionosphere does not behave as a simple resistive slab for electric field time scales less than a few seconds. Time variation of spacecraft-measured high-latitude electric and perturbation magnetic fields is difficult to distinguish from spatial structuring that has been Doppler-shifted to a non-zero frequency in the spacecraft frame. However, by calculating the frequency-dependent amplitude and phase relations between fluctuating electric and magnetic fields we are able to show that low frequency fields (