  To test the standard flare model (CSHKP-model), we measured the magnetic-flux
change rate in five flare events of different GOES classes using
chromospheric/photospheric observations and compared its progression with
observed nonthermal flare emission. We calculated the cumulated positive and
negative magnetic flux participating in the reconnection process, as well as
the total reconnection flux. Finally, we investigated the relations between the
total reconnection flux, the GOES class of the events, and the linear velocity
of the flare-associated CMEs. Using high-cadence H-alpha and TRACE 1600 A image
time-series data and MDI/SOHO magnetograms, we measured the required
observables (newly brightened flare area and magnetic-field strength inside
this area). RHESSI and INTEGRAL hard X-ray time profiles in nonthermal energy
bands were used as observable proxies for the flare-energy release rate. We
detected strong temporal correlations between the derived magnetic-flux change
rate and the observed nonthermal emission of all events. The cumulated positive
and negative fluxes, with flux ratios of between 0.64 and 1.35, were almost
equivalent to each other. Total reconnection fluxes ranged between 1.8 x 10^21
Mx for the weakest event (GOES class B9.5) and 15.5 x 10^21 Mx for the most
energetic one (GOES class X17.2). The amount of magnetic flux participating in
the reconnection process was higher in more energetic events than in weaker
ones. Flares with more reconnection flux were associated with faster CMEs.
