Figure 10: With a nonvanishing electric field, the new radial location emerges, which is shown as the dashed circular curve above. In this case, also, the embedding functions can be divided into two categories, separated by a critical one. The critical curve is subtle to define, since the conical singularity in the critical curve of Figure 9 can occur either at the location of the background event horizon, or at . Here, we will choose the latter, which will be further justified later.