These devices share their name with the Smale-Williams strange attractor, which is formed by an iterated map on the solid torus. In fluidic control systems, (-5[1])these devices name and toggle a type of valve that can be either “normally open” or “normally closed.” The vector potential of one of these devices only has a theta component. These devices (15[1])name the rotational component of a Helmholtz decomposition, which is (-5[1])a (15[1])vector field (15[1])with zero (*) divergence. A toroid (10[1])is a circular one of these devices used to confine plasmas in (-5[1])tokamaks. (-5[3])Ampere’s law (10[1])can be used to show (-5[1])that the magnetic field in one of these (10[1])devices (10[1])is “mu-naught (10[1])I (10[1])N,” where N is the number of turns per unit length. (10[1])For 10 points, name these coils of wire commonly used as inductors. (10[1])■END■ (10[2]0[2])