  The reported onset temperatures of the flash transition in cubic zirconia
single crystals have been analyzed in the present note. The analysis for
high-temperature low-field data gives an activation energy of 0.99 eV for the
charge transport, which agrees well with the measured ionic conductivity data
in cubic zirconia single crystal. Electrical reduction is believed to play an
additional role under low-temperature high-field conditions, facilitating
electrical/thermal runaway under more modest conditions.
