Same as in Figure  5. (a) 2001 April 10 X2.3 flare occurrence that peaked at UT 05:06. HEP fluxes are enhanced more than 14 hr prior to the flare. Protons with energy higher than 1, 5, and 10 MeV are close to the post-flare level. Soon after the explosive phase the system bifurcates into long-living (⩾ 8 hr) self-organized state. (b) Series of M-class and C-class flares (marked by blue arrows) that occurred prior to the X-class flare (peaked at UT 20:01 on 2003 June 11) were not able to elevate a HEP flux prior to the flare. The post-flare state is short living (~ 1 hr) without any trace of bifurcation.