Defensive spell or item that would hurl an attacker back?

[Eaglejarl]

I'm trying to write a scene where a bunch of physical fighters (humans) charge at a mage and, before they get to him, they are hurled back.

There isn't a lot of space; the room is only about 15' on a side and the door leads to a round corridor 6' in diameter. The attackers will start within about 5' of him. I mention all this because my first thought was Antilife Shell, but that is a 10' emanation and it prevents people from entering, it doesn't say that it would eject anyone already in the radius.

I'm looking for a non-Psionic, non-Epic way to do this according to RAW. There must be an item or spell (in a Contingency) that will work.

Any thoughts?

[DeltaEmil]

Forcewave from the Spell Compendium will do that.

[Gildedragon]

Sculpted Cyclonic Blast

Defenestrating Sphere

[Baroknik]

You may be able to use the Clouting weapon property to some effect as well. CArcane

[Regissoma]

Explosive Spell to any aoe spell that does damage if you can afford the +2 to spell level or get a free metamagic schimick can do what you want. Its also the basis of the Locate City Bomb.

[Eaglejarl]

Y'all are great. Thanks.