From Dragon Ball Encyclopedia, the ''Dragon Ball'' wiki
The Solar Kamehameha (太陽系 破壊 かめはめ波, Taiyōkei Hakai Kamehameha; Literally meaning "Solar System Destroying Turtle Destruction Wave") is an energy beam wave attack used by Cell in his Super Perfect form.
Super Perfect Cell stores up a huge amount of energy as he prepares a Super Kamehameha. He then brings his hands forward and fires the attack which has enough power to destroy not only Planet Earth, but the whole Solar System.
Dragon Ball Z
Super Perfect Cell used this attack at the end of the Cell Games against Son Gohan in his Super Saiyan 2 form, who then counterattacked with the Father-Son Kamehameha. During the Energy Struggle, Super Perfect Cell overpowered Super Saiyan 2 Gohan several times due to breaking the young Saiyan's arm with an energy blast intended for Vegeta. As Super Perfect Cell was about to finish off Gohan, however, Vegeta distracted Super Perfect Cell with a Big Bang Attack. With Super Perfect Cell distracted, Super Saiyan 2 Gohan used all of his power to completely annihilate him.