And invert it.

SELECT INVERSE command.

Wave systems

Something like this. I used Blur on this area. As a result I get this.

Wave systems

I decided to put some texture for better look.

Use layer styles for this purpose.

Wave systems

You can
 
actually play with scale and depth. I did it like that .

Wave systems

I used color balance to reach this color. Create a new Adjustments Layer.

Wave systems



Wave systems



Wave systems