Here are some things to try:
-The Glow effect (set the intensity up, and the threshold down to really blow out the bloom. The radius controls the size of the bloom).
-Exposure (Might be useful to apply in conjunction with Glow).
OR
-Duplicate the layer. Set the top layer to “add” mode, and apply fast blur. Adjust the blur and transparency of the layer to taste.
Good luck,
Brian