The transient properties of laser-cooled two charged particles in a Paul tr
ap are studied numerically. We find the existence of characteristic lifetim
e of an attractor, which is thought to be an important feature of the trans
ient dynamics of the weakly dissipative system. The theoretical analysis sh
ows that it is caused by pseudo-periodic orbit which is the residual sign o
f periodic orbit of the focus-saddle bifurcation. Study of dissipative coup
led standard maps shows that this is a general conclusion for weakly dissip
ative system.