The new Psi Warrior Fighter subclass has the feature Psionic Power which has the following option:
Psionic Strike. You can propel your weapons with psionic force. Once on each of your turns, immediately after you hit a target within 30 feet of you with an attack and deal damage to it with a weapon, you can expend one Psionic Energy die, rolling it and dealing force damage to the target equal to the number rolled plus your Intelligence modifier.
Is this ability affected by critical hits like a Paladin's Divine Smite or does it deal extra damage independent from the attack?