The Light Beam is an upgrade of Samus' charge beam. The Light Beam can be acquired from Dark Agon Wastes in Metroid Prime 2: Echos.
The Light Beam is capable of handling mass amounts of Dark Creatures, and is a far more useful weapon against the ing than the Dark Beam. The Light Beam is similar toe the plasma beam form Metroid Prime. Both of the beams have the ability to set the enemies ablaze. Additionally, the appearance is similar to that of the wave Beam. Another function of the Light Beam, aside from dealing with the Ing, is its ability to open White Doors. As with many other weapons in the Metroid Prime series, when ammo is depleted, Samus can charge the weapon and use it for an ordinary shot.
Once the Grand Windchamber is recovered within the game, Samus can use Sunburst, which could most easily be described as a combo for the Light Beam. It creates an orb of light that destroys Dark enemies.
The Light Beam appears similar to the Plasma Beam found in Metroid Prime. Additionally, the Wave Beam is similar to ethe Nova Beam of Metroid Prime 3.