Eldritch Dome

When the castor kneels or is knocked prone as an action a dome of crackling energy surrounds the caster. All creatures within 5 feet radius (10 feet diameter) of the caster takes 1d4+2 force damage and pushed back 10 feet.

The spell forces creatures farther away when you reach higher levels: 15 feet at 5th level, 20 feet at 11th level, and 30 feet at 17th level.