  Magnetic reconnection is an important physical process in various explosive
phenomena in the universe. In the previous studies, it was found that fast re-
connection takes place when the thickness of a current sheet becomes on the
order of a microscopic length such as the ion larmor radius or the ion inertial
length. In this study, we investigated the pinching process of a current sheet
by the Lorentz force in a low-{\beta} plasma using one-dimensional
magnetohydrodynam- ics (MHD) simulations. It is known that there is an exact
self-similar solution for this problem that neglects gas pressure. We compared
the non-linear MHD dynamics with the analytic self-similar solution. From the
MHD simulations, we found that with the gas pressure included the implosion
process deviates from the analytic self-similar solution as t {\rightarrow} t
0, where t 0 is the explosion time when the thickness of a current sheet of the
analytic solution becomes 0. We also found a pair of MHD fast-mode shocks are
generated and propagate after the formation of the pinched current sheet as t
{\rightarrow} t 0 . On the basis of the Rankine-Hugoniot relations, we derived
the scaling law of the physical quantities with respect to the initial plasma
beta in the pinched current sheet. Our study could help us to estimate the
physical quantities in the pinched current sheet formed in a low-\b{eta}
plasma.
