The authors explore solar flares by applying physics and theoretical investigations.

A thorough introduction to solar physics based on recent spacecraft observations. The author introduces the solar corona and sets it in the context of basic plasma physics before moving on to discuss plasma instabilities and plasma heating processes. The latest results on coronal heating and radiation are presented. Spectacular phenomena such as solar flares and coronal mass ejections are described in detail, together with their potential effects on the Earth.

In May 1998 a hundred renowned scientists from 20 different countries met at the Max-Planck-Institut für Aeronomie to communicate their latest results and ideas in astrophysical and space plasma, as a follow-up to previous similar meetings which were held in Varenna, Abastumai, Potsdam, Toki and Guaruja. The main papers emerging from this meeting are collected in this volume. They deal with fundamental plasma phenomena, particle and radiation processes in astrophysics and space physics as the origin of magnetic activity, the basic mechanisms of particle acceleration and plasma heating common to plasma in galaxies and at the sun as well as in planetary magnetospheres. New observational results from YOHKOH, SOHO and other missions are presented. Using these, the basic physical processes leading to coronal heating and solar/stellar wind acceleration are discussed. Other topics are the microphysics of shock waves and transport phenomena in collisionless plasmas and the physics of thin plasma boundaries. The volume also treats the ionic composition of plasma and dust in the Universe and their observability in the solar system. A CD-ROM is attached which adds a valuable multimedia component, illuminating results of observations, theory and simulations. Everyone interested in astrophysical plasmas, its radiation and charged particle aspects, and advanced or even beginning students will find references to nearly all modern aspects of plasma astrophysics and space physics as well as an overview of current research results.

This report describes a radio investigation of traveling ionospheric disturbances carried out near Boulder, Colorado, over a 1-year period from June 1967 to June 1968. The three-dimensional motions of F2 layer disturbances were measured by the high frequency Doppler technique with spaced transmitters and at several probing frequencies. Horizontal motions were determined by cross-correlating three signals on frequencies near 5 MHz, whose reflection points were approximately at the corners of a horizontal equilateral triangle with 40-km sides. Vertical motions were determined from cross-correlation of signals on frequencies of 3.3, 4.0, and 5.1 MHz, whose reflection points were aligned vertically.