  We calculate the rate of thermal Schwinger pair production at arbitrary
coupling in weak external fields. Our calculations are valid independently of
many properties of the charged particles produced, in particular their spin and
whether they are electric or magnetic. Using the worldline formalism, we
calculate the logarithm of the rate to leading order in the weak external field
and to all orders in virtual photon exchange, taking us beyond the perturbative
expansion about the leading order, weak coupling result.
