  Chirped dynamically assisted pair production in spatial inhomogeneous
electric fields is studied by the Dirac-Heisenberg-Wigner formalism. The
effects of the chirp parameter on the reduced momentum spectrum, the reduced
total yield of the created pairs for either low or high frequency one-color
field and two-color dynamically assisted combinational fields are investigated
in detail. Also, the enhancement factor is obtained in the later two-color
field case. It is found that for the low frequency field, no matter whether it
is accompanied by the other high frequency field, its chirping has a little
effect on the pair production. For the one-color high frequency field or/and
two-color fields, the momentum spectrum exhibits incomplete interference and
the interference effect becomes more and more remarkable as chirp increases. We
also find that in the chirped dynamically assisted field, the reduced total
yield is enhanced significantly when the chirps are acting on the two fields,
compared with that the chirp is acting only for the low frequency strong field.
Specifically, by the chirping, it is found the reduced pair number is increased
by more than one order of magnitude in the field with a relative narrow spatial
scale, while it is enhanced at least two times in other case of field with
larger spatial scales or even in the quasi-homogeneous region. We also obtain
some optimal chirp parameters and spatial scales for the total yield and
enhancement factor in different scenarios of the studied external field. These
results may provide a theoretical basis for possible experiments in the future.
