Acceleration and vacuum temperature

The quantum fluctuations of an "accelerated" vacuum state, that is, vacuum fluctuations in the presence of a constant electromagnetic field, can be described by the temperature T _M. Considering T _M for the gyromagnetic factor g=1 we show that T _M(g=1)=T _U, where T _U is the Unruh temperature experienced by an accelerated observer. We conjecture that both particle production and nonlinear field effects inherent in the Unruh accelerated observer case are described by the case g=1 QED of strong fields. We present rates of particle production for g=0, 1, 2 and show that the case g=1 is experimentally distinguishable from g=0, 2. Therefore, either accelerated observers are distinguishable from accelerated vacuum or there is unexpected modification of the theoretical framework.