Those "waves" are not really because of low light. Low light is responsible for noise that you get but not the waves.
Those waves are coming from a fact that you're using a light source that is very likely emitting at frequency of 50Hz (common light bulbs connected directly to a power source).
Your camera shoots faster than your light source is refreshing and you end up with 240 frames in a second which are not filled with light of same power.