The Fleming’s Left hand rule can be used to determine the direction of the magnetic field. The thumb, forefinger, and middle finger of the left hand are right perpendicular to each other, therefore the thumb points to the direction of magnetic force, the middle finger to the direction of current, and the forefinger to the direction of magnetic field, according to the rule. The direction of the positively charged particle is west, so the direction of the current will be west as well. Because the magnetic force is directed north, the magnetic field will be directed upward, according to Fleming’s Left Hand Rule.