Understanding of critical slowing down

Have been wondering why when approaching the critical point the time revolution would slow down...

From one of the Japanese textbook, near the critical point, when the difference between whether to have a symmetry is infinitsemal, fluctuations are relatively amplified. After reading this I wondered whether it is according to the fluctuations are turned something macroscopic, so the change must take some time? However this explanation is something not so pleasing....T_T

Today I started to read the chapter concerning phase transition in Landau (So great are his theoretical series!!!!!!) and found a pleasing-to-me explanation though it is a phenomenological explanation, that is when approaching the critical point, the free energy becomes flat with respect to the order parameter, thus the "restoring force", driving the system to its corresponding equilibrium state would be rather weak, which in sum would enlarge the time revolution scale.

そうか！という感じ。

And now also more understandable that why in the class the Brownian motion is mentioned. It is also the macroscopic effect of many microscopic actions and is in a slow time scale, and also where fluctuations take important place. In common they share the phenomenological coefficients and the random force(not exactly)? But the ways to deal with random process and fluctuations still seem difficult to me now....which makes the preference to experimentalist to theorist stronger and stronger...

website you can see the critical slowing down:
http://www.ibiblio.org/e-notes/Perc/rel.htm

2011/01/16