It's not static. Strobes using switching power supplies have the ground floating at 240/2v=120v. You need to ground the equipment via a proper earth connection to eliminate the 120v potential on the equipment ground.
Get a piece of long wire. COnnect one to any metal component on your strobe and the other to the earth socket at the plug. Might be easier if you just cut the two pin plug and change the socket to a three pin