WDS previously: Let the field be of form (Bx,By,Bz) = (0, 0, K*x) ES: Whoa there!? Your magnetic field fails to satisfy the Maxwell equation div B = 0. WDS: It *does* satisfy div B=0. [It is not however a vacuum static solution -- this B-field arises from a constant current density in the y-direction: curl B = (0,-K,0). That's fine.]