Toroidal Radius ความหมาย คือ in a solar loop structure, it is the distance from the axis of the loop to the center of the "semi-circle" that the loop forms. Half of the distance from one loop footpoint to the other loop footpoint. For a doughnut, it is the distance from the center of the doughnut hole to the center (circular axis) of the pastry. See also Poloidal Radius.