We present an overview of solar flares and associated phenomena, drawing upon a wide range of observational data primarily from the RHESSI era. Following an introductory discussion and overview of the status of observational capabilities, the article is split into topical sections which deal with different areas of flare phenomena (footpoints and ribbons, coronal sources, relationship to coronal mass ejections) and their interconnections. We also discuss flare soft X-ray spectroscopy and the energetics of the process. The emphasis is to describe the observations from multiple points of view, while bearing in mind the models that link them to each other and to theory. The present theoretical and observational understanding of solar flares is far from complete, so we conclude with a brief discussion of models, and a list of missing but important observations.

The solar atmosphere, above the Sun's surface layers, reaches mega-kelvin temperatures and high levels of dynamic activity through processes involving a pervading magnetic field. This book explores one of the principal means of understanding the solar atmosphere, its ultraviolet and soft X-ray emission. The ultraviolet and X-ray spectra of the Sun's atmosphere provide valuable information about its nature - the heat and density of its various parts, its dynamics, and chemical composition. The principles governing spectral line and continuous emission, and how spectral studies lead to deductions about physical properties, are described, together with spacecraft instrumentation from Skylab, SolarMax, Yohkoh, SOHO, TRACE, and Hinode. With introductions to atomic physics and diagnostic techniques used by solar spectroscopists, a list of emission lines in ultraviolet and soft X-ray regions, and a glossary of terms, this is an ideal reference for graduate students and researchers in astrophysics and solar physics.

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The Solar Eclipse Corona Imaging System (SECIS) was used to record high‐cadence observations of the solar corona during the total solar eclipse of 1999 August 11. During the 2 min 23.5 s of totality, 6364 images were recorded simultaneously in each of the two channels: a white light channel, and the Fe xiv (5303 Å) ‘green line’ channel (T∼2 MK). Here we report initial results from the SECIS experiment, including the discovery of a 6‐s intensity oscillation in an active region coronal loop.

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