Strings in background electric field, space/time noncommutativity and a new noncritical string theory

Searching for space/time noncommutativity we reconsider open strings in a c onstant background electric field. The main difference between this situati on and its magnetic counterpart is that here there is a critical electric f ield beyond which the theory does not make sense. We show that this critica l field prevents us from finding a limit in which the theory becomes a fiel d theory on a noncommutative spacetime. However, an appropriate limit towar d the critical field leads to a novel noncritical string theory on a noncom mutative spacetime.