I can get close by using Render > Fibers, and using Free Transform to stretch them vertically, and finally using a Levels layer to adjust the contrast, but I could not get the lines as fine as in your example.
I believe that was done with a brush. Create a brush from a long narrow triangle - the custom paths shape tool has already a triangle shape that can be stretched when creating it. From the brush controls enable only Size Jitter from Shape Dynamics and set it to 100% and from the Brush Tip Shape adjust spacing as desired.
For color gradient, create a gradient layer on top and make it a clipping mask (Ctrl + Alt + G)
I guess if you wanted really fine lines
Honestly, I don't see a problem with the "fineness" of the lines in my example, as they are a single pixel in width, but there's always the possibility of creating any effect at a much larger size and downsizing.