Different beams have different effects when shot at a Luminoth Light Beacon:
Annihilator Beam: Supercharges beacon for an extended amount of time and causes any surrounding Ing to walk into the light causing it to die. This is very helpful if you are low on energy or ammunition.
Dark Beam: Temporarily extinguishes beacon. Note: Only the Light Beam can change it back, or you can wait for it to change back by itself.
Light Beam: Charges beacon for an extended amount of time.
Power Beam: Charges beacon and offers protection from Dark Aether Atmosphere for a short amount of time.