1) Make a new document, anysize doesn't matter. Make sure your background is WHITE. Set your foreground color to WHITE aswell.
2) Apply Filter>Render>Clouds. Now grab the eraser tool and make some squigly eraser marks on the cloud render:
3) Apply Filter>Blur>Radial Blur with these settings:
4) Press CNTRL+U and use these hue settings:
5) Duplicate the layer and set the top layer blending to Vivid Light:
6) Your image should be looking like a mass of inferno like below:
