Fire and Ice
Last night the
Twin
Cities Photography Group Inc. organized an event with the
Fire Jam Dancers. It
was a blast - but there is much to learn. The moving flame
illuminates the performer, but the light is very finicky - it ebbs
and flows and moves to unexpected places. The only hope (for me) is
to shoot it like the fireworks: manual focus using live view, then
play with exposure to get the faces lit but not blurry. For
instance this has been shot in 1/8s at f/1.4 (ISO 100).

You could try using a second curtain sync strobe to freeze the
movement at the end but the light moving in close proximity of the
performer will lit her enough to generate visible blur:
Here is a selection of the photos taken by other
participants.