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dThe book doesn't go into it. It just analyzes an equivalent circuit. The helicity of the current is hidden in the word inductor. Inductors are helical wires. I forgot the references I had when I studied electromagnetic theory. However, the bistable mode is part of our "current lore" concerning conductors. It is consistent, fully, with our knowledge of the electromagnetic field. I'll present a heuristic argument that I hope makes it more plausible. Think of a liquid conductor in motion that is initially neutral in charge and current free. On the atomic scale, it consists of at least two different charge carriers. It has low mass charge carriers, an example of which could be conduction electrons. However, since it is liquid the atoms that held the low mass charge carriers are also free to move. So there is a heavier charge carrier, which in my example is the iron ion the conduction electron leaves behind. I am being careful to generalize this, so I don't want to stick to the idea that the free carriers have to be electrons. In an electrolytic solution, the free carriers can be ions of similar mass. In most metals, the low mass free carrier are conduction electrons. In some metals (e.g., aluminum), the low mass free carriers are positively charged holes. In solid state physics, we usually concentrate on the low mass charge carrier because the atoms left by the low mass free carriers are fixed in place. However, in a liquid both types of charges can move freely. So in a liquid conductor, there are always positive and negative free carriers of charge. In initially, our liquid has no electric current. Take a force and move the liquid in a helical path. I'll generalize and say that helical means having a chiral shape. In the earth system, the helical motion is caused by a combination of rotation and convection. Now apply a short lived magnetic field to the liquid, which is moving in a helical path. An external magnetic field is turned on for a very short time and turned off. So far, the liquid doesn't generate its own magnetic field. There is only the external field. During the time that the external magnetic field is turned on, there is a type of charge separation. The negative charges may be forced to start moving slowly clockwise through the liquid. However, the positive charges will be given an impulse in the opposite direction. The positive charges may start to move slowly counterclockwise. There is now an electric current, although the net charge density of the liquid is zero. The external magnetic field is then turned off. Both types of charge carriers now generate their own magnetic dipole. However, the two dipoles don't cancel out. They are pointing in the same direction! Because although the charge carriers are moving in opposite directions, they are also opposite in electric charge. Therefore, an internal magnetic field is now being generated by the charge carriers. The internal magnetic field forces the charge carriers to move faster in the same direction. The magnetic dipole gets stronger, and the magnetic field gets stronger. The energy is coming from the rotational kinetic energy of the liquid, and the angular momentum stays at zero because the free carriers are moving in opposite directions. The angular momentum of the positive free carriers is always equal in magnitude but opposite in direction to the angular momentum of the negative free carriers. Eventually, the magnetic dipole reaches a peak, determined by the physical and electrical properties of the liquid. The liquid now has a magnetic dipole, and there is no external magnetic field on it. This magnetic dipole is energetically more stable, by a small amount, than the state of the nonmagnetic state. So it stays. No trace of the external magnetic field, except for the orientation of the internal magnetic field. The field is self perpetuating, as long as the helical motion is maintained. Actually, the energy to maintain the magnetic field is coming from the helical motion, but this is a small drain. There is a catch. There is another state of equal stability where the magnetic dipole is pointing in the exact opposite direction. If another external magnetic field is turned on and then off, the process could roll the other way. A magnetic dipole can form in the opposite direction. This self-generated magnetic dipole would be more likely to form with metal conductors than electrolytes, because the low mas free carriers in a metal are much lighter than ions. A conduction electron or a hole in a metal are about the mass of an electron in a vacuum (not exactly, but close), while the ions are thousands of times more massive than an electron. So the low mass free carriers move much faster. The same goes for plasmas, like the hot gas in the sun. The hot plasma contains electrons, which move faster. The helicity of the path is necessary for this bistable state, since to form the system has to "know" the difference between clockwise and counterclockwise. However, long ago and far away I did some example showing that the helicity was necessary. I am not sure what the explanation is for the 22 year cycle on the sunspots. I would think from this heuristic argument that the bistable state wouldn't have a ture periodicity. However, I conjecture that the switching of states is driven by the orbit of Jupiter. A Jovian year is 11.5 earth years. The magnetic field of Jupiter and the magnetic field of the sun may be interacting. This is only a conjecture on my part, so please feel free to criticize.