Electron
trapping
is
governed by
collisional
deflection
times
:
t_trap(E)
~ t_defl(E)
~ E^3/2 / n_e
trapping
times in
flare
loops
t_trap ~ 1-5 s
n_e ~ 10^11 cm-3
CGRO/BATSE
Aschwanden
et al. 1997