  We investigate rapid TeV flaring in markarian 501 in the frame of a
time-dependent one-zone synchrotron self-Compton (SSC) model. Inthis model,
electrons are accelerated to extra-relativistic energy through the stochastic
particle acceleration and evolve with the time, nonthermal photons are produced
by both synchrotron and inverse Comtpon scattering off synchrotron photons.
Moreover, nonthermal photons during a pre-flare are produced by the
relativistic electrons in the steady state and those during a flare are
produced by the electrons whose injection rate is changed at some time
interval. We apply the model to the rapid flare of Markarian 501 on July 9,
2005 and obtain the multi-wavelength spectra during the pre-flare and during
the flare. Our results show that the time-dependent properties of flares can be
reproduced by varying the injection rate of electrons and a clear canonical
anti-clockwise-loop can be given.
