Multi-wavelength observations of the pre-cursor phase of solar flares

Observational studies of the pre-cursor phase of solar flares have shown that there are many and varied signatures that may or may not indicate the probable onset of a flare. Combining data from Yohkoh, SOHO and TRACE and more recent observations from RHESSI, SOHO and TRACE we, investigate the relationships between the different manifestations of pre-flare behaviour in two solar flares with a view to determining how they are related to the subsequent flare energy release. We find that in one case the preflare activity seems strongly related to the subsequent flare and probably represents a build-up of energy in the active region prior to flare onset. The second case we find to be less clear cut suggesting that significant further work remains to be done in order to determine which pre-flare signatures are most useful in indicating the build-up to Rare onset. (C) 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.