Ultra-strong Elelctric Fields and Vacuum Breakdown: Search for an   Astrophysical Scenario
  In some models of $\gamma$-ray bursts super-strong electric fields ($E\sim 10^{14} {\rm statvolt cm}^{-1}$) have been surmized. Such large fields may provide copious pair production through vacuum polarization. Here we examine various astrophysical scenarios where huge electric field can be present. It is shown that when the conditions for quantistic vacuum breakdown are met, pair creation through conventional processes is likely to be always more important. Although of great physical interest, quantum pair production seems therefore of little astrophysical relevance. 
Aldo Treves (University of Como), Roberto Turolla (University of   Padova) and S.B. Popov (Sternberg Astronomical Institute)