Proton torpedoes: why are they called that?

[Vultur]

What does the 'proton' in 'proton torpedoes' mean? It can't be the proton-proton fusion reaction, surely? That's not very useful in a bomb...

Unless it's just a torpedo filled with hydrogen ions

[Darth Paxis]

According to Wookieepedia's article on them, the explosion is caused by a baradium charge detonated by a Proton detonator. I'm not sure how much help this is though, as the article also says that the issue has not been explored very much, so this may not be canon.

[Ghost Rider]

Locking because this is the same level of stupidity as asking what's the meaning behind Turbolaser.