Theory Of Unipolar Induction Phenomenon And Its Possible Test

Unipolar induction is a special electromagnetic induction phenomenon which occurs when a cylindrical magnet rotates around its symmetrical axis. There are all kinds of theoretical explanations on it, but it is still an open question whether the magnetic lines co-rotate with the magnet, which was puzzling most of physicists and heated debated. There are mainly two hypotheses on it, one is the M hypothesis which assumes that the force lines co-rotate with the magnet, and the other is the N hypothesis which assumes that they remain rest while the magnet rotates.This thesis mainly goes on some studies on theories and experiments of unipolar induction. We introduce the theories and some experiments for testing it, especially the classical open-circuit experiments at the beginning of twenty century which were done by replacing the wire with a cylindrical capacitor mounted coaxially around the spinning magnet. Subsequently, we analyze the merits and disadvantages of those experiments.Djuric ?made use of a mathematical mode of the generalized homopolar generator to analyze the classical open-circuit experiments, and then conclude that no experiment with the generalized or classical homopolar generator can resolve the puzzle, which one of the two logically possible hypotheses is correct, the moving or nonmoving force line hypothesis. In particular, we analyze in detail the open-circuit experiment of Bartlett et al. in 1977 which is different from the classical ones, and point out the disadvantages of their experiment in devise, and assume that their experimental conclusion is suspectable. Then, we suggest a possible improved method. However, we are illumed by investigation production of a group of geography research which confirms that Earth's inner core is rotating faster than the mantle and crust at about 0.30 to 0.50 per year, thus the experimental test of the M or N hypothesis will promote the development of the geomagnetic origin. Lastly, based on the TN type experimental method which was advised by Gillies et al. to use for testing the Faraday law in"differential form", and devise a new experimental scheme to resolve the puzzle of unipolar induction, and the experimental design is a torsion balance which made of parallel capacitors. Besides, we point out some mistakes in concept in the paper of Gillies et al.