Then go to Filter >> Render >> Clouds, and you should get something like this.

Then you'll go to Filter >> Blur >> Motion Blur and have the angle set to O, and choose a large number, I chose 250. You'll repeat the blurring a few times to get the desired effect, and to save the hassle just press Ctrl + F to repeat the action.

This should be the final image.

And here it is in a different colour.

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