Unless you want an image with a transparent background, you don't. What you asking of is surely possible, but then the corona won't have the same shiny look as in the technique described above.

For transparent corona:
1. Make a solid layer and will it with Filter > Render > Clouds using the same colours you used for your sun.
2. Image > Adjustments > Brightness/Contrast if the colours are too dim.
3. Make a new layer, switch background and foreground colors to BW. Apply Filter > Render > Clouds to the new layer.
4. Switch the second layer to Color Dodge mode.
5. Merge these two layers.
6. Select the star disc visible pixels and Select > Modify > Border.
7. Save the to a new channel for better control of what you're going to get.
8. Switch to this channel and turn everything else off. Smooth it to your liking. Mine was Filter > Blur > Radial Blur, Method: Spin, Quality: Best, Amount: 100, then Filter > Blur > Radial Blur with Method: Zoom, Quality: Best, Amount: 50
9. Make a new channel, run Filter > Render > Clouds then Filter > Render > Difference Clouds till the pattern you get is rather complex, usually twice or thrice is enough
10. Load this new channel as a selection, switch to the channel you've been working on previously and fill the selected areas with black.
11. Image > Adjustments > Brightness/Contrast on the resulting channel if you feel there are not enough white areas on шею
12. Apply this channel as a mask to your corona layer.
13. Merge it with disc layer, delete the black background and save as a PNG with transparency.
14. To get rid of possible "artifacts" you may want to check youк star on a lighter background and remove the unwanted corona parts a soft eraser brush.

Sorry, no pictures this time.