Small scale energy release and the acceleration and transport of energetic particles Hugh Hudson 1 and Nicole Vilmer 2 1 SSL/UCB Berkeley, CA USA 94720 hhudson@hhudson@ssl.berkeley.edu 2 LESIA, Observatoire de Paris, Meudon, FR 92195 nicole.vilmer@obspm.fr Summary. We report on results presented at the sessions of Working Group 1 at CESRA 2004, which covered the topic area of the title of this paper. The working- group participants are listed in the Appendix, and the topics discussed have been brought together in several general areas of focus. The emphasis on the discussion is from the point of view of radiophysics. We organize the material by presenting new constraints imposed by the recent high-energy and radio observations. We note though that multi-wavelength knowledge is generally vital in understanding all of the phenomena involved. The new constraints include exciting new millimeter-wave discoveries, among others. We then place these observations into the framework of our knowledge of the acceleration and propagation of high-energy particles, and of their radio emission mechanisms. The RHESSI 3 results are the most distinctive in this time frame, and they have made possible several new advances. 1 Introduction The techniques of solar radio astronomy have historically led the way in our studies of the non-thermal behavior of the solar corona. In recent decades X- ray and EUV observations have begun to approach the resolution (the arc sec range) of the radio observations at mm/cm wavelengths (e.g. those of the VLA 4 and NoRH 5 ) and we now find ourselves in a happy era in which these very different wave bands can all contribute to our understanding. This article discusses material presented in the CESRA 2004 working- group sessions on the subject named in the title of this chapter; please see the CESRA 2001 proceedings [1] for continuity. Although we deal with multi- wavelength views of these topics, our perspective is that of solar radiophysics (see also [2] for recent reviews and discussions in the context of the FASR 6 3 Reuven Ramaty High-Energy Solar Spectroscopic Imager (space observatory) 4 Very Large Array (Socorro, New Mexico) 5 Nobeyama Radio Heliograph (Nobeyama, Japan) 6 Frequency-Agile Solar Radiotelescope (in development)