Hey, i downloaded these a LOOOOONG time ago, and forgot who made them and then used them in some wallpapers I made, a few of which are uploaded on my account. I'll credit you now, since I found you. And really awesome brushes btw
You first make the background layer black and than put the brushes on in the color white. Than you duplicate the layer and add a Gaussian Blur and made it 5% and make that layer 50% opacity. Than make a new layer and use the gradient tool and put that down and than in layer effects for that layer make it color. Hope that helped.