Grav Pulse

Use this Stratagem in either:
Your Movement phase, when an AA REPULSOR FIELD unit from your army Falls Back. Until the end of the turn, that unit is still eligible to shoot even though it Fell Back.
Your opponent's Charge phase, when an AA REPULSOR FIELD unit from your army is selected as a target of a charge. Until the end of the phase, subtract 2 from charge rolls made for any unit that declares a charge against that REPULSDR FIELD unit.