The singularity-based mathematical model of black holes has long proved its great worth, by providing a solid basis for theoretical constructions of these cosmological behemoths. However, this model is based on certain basic physical assumptions which might not adequately account for the remarkable and notable magnetic fields which would be generated by a stable, rapidly rotating “black hole” torus.
There are compelling reasons to consider a black hole torus as the ultimate superfluid, superconductive object. In this cosmological ring, or donut, every location is moving in precisely the opposite direction as a point in the mirror position on the opposite side of the torus. The result of that dynamic is simple and clear. A powerful magnetic field, perpendicular to the plane of the torus, would fill the open space in the center of the torus.
At the same time, the one-way flow of superconductive material would result in a magnetic field sheath, along the entire course of the torus. These two fields (the field in the open center of the torus and the torus-enveloping field) would meet, contiguously, at the inner wall of the torus.
An accretion disk presents an impact area for the torus-encircling magnetic field. Here, the circularly enveloping field impacts directly into the accretion disk, which would distort the field lines enough, within the central plane, to spark magnetic reconnection events. Crucially, the orientation of the crossed field lines (think of the left or right sides of the “x” of the reconnection) would cause material to be directly injected into the black hole via the central plane, as opposed to relying on a slow spiraling gravitational accretion. This process adds to the general turbulence of the event horizon region, since the reconnection would send some material in the opposite direction from the black hole, as well.
Reconnection also seems likely at the inner wall region of the torus, at the nexus of the two fields, although the different architecture of the fields there (representing the top or bottom portions of the “x” of the reconnection) would likely result in a movement of material very close to perpendicular of the plane of the galaxy. Also, free material would tend to be less abundant there in a typical galaxy, compared with the often-busy accretion disk area at the outer aspect of the torus. Perhaps material occasionally ejected by inner reconnection events are responsible for many of the intriguing radio filaments near the center of our own galaxy, which are so clearly evident in the exciting new MeerKAT images.
Taking a step back, let us look at the magnetic fields of other similar objects we are familiar with. A toroid (a torus wrapped in current-carrying wires), our own Earth, and a neutron star, are all examples of objects that create their own magnetic field.
The magnetic field of a toroid is dictated by the current-carrying wire, which is wrapped around a torus, resulting in a magnetic field within the body of the torus. That is just about the exact inverse of the situation with a toroidal or torus black hole, where the torus carries the current, and the open space in the center of the torus becomes the location of the magnetic field. Yet the very same principle applies, as with a simple toroid.
The magnetic field of the Earth is centered upon a metallic core. Magnetic field lines impact directly on this central core, passing through the Earth at the polar areas to do so. That is the opposite of the situation with a toroidal black hole, where instead of a central core driving the magnetism, there is nothingness at the center.
Neutron stars are where it really starts to get interesting. When you think of cosmological objects that might be superconductive, neutron stars jump to mind, due to their extreme nature. However, the self-generated magnetic fields which ferociously batter the star put a damper on any thoughts of total superconductivity, as the power of these incoming fields overwhelm any chance of the star achieving a complete Meissner state.
A neutron star does not attain complete superconductive status due to the extreme magnetic bombardment it endures. But a superfluid neutron star with a well-organized magnetic field can be a precursor to a torus black hole.
While neutron stars are generally considered to be spherical in nature, or even prolate (football-shaped) due to their magnetic fields, there is good reason to think a monster neutron star which has taken up enough orbiting matter would begin to compress vertically, into an oblate spheroid (think of a ball which you have partially flattened out by pressing your hand down on it). Imagine this oblate spheroid with powerhouse magnetic fields blasting down on the polar regions. As the spheroid compresses, the north pole gets closer and closer to the south pole of the star. The pounding influence of the magnetic fields continue, defeating any movement towards total superconductivity. Meanwhile, the pole areas draw even closer together, resulting in something that is approaching a torus shape, but where the hole has not completely broken through yet.
Once the neutron star gets so oblate that the dimpled north pole meets the dimpled south pole of the star, a central channel would naturally open, as the star makes the final conversion from a flattened ball to a torus. Once that conversion occurs, complete superconductivity would be instant.
With most of the magnetic fields now safely separated from the torus, any remaining magnetic fields within the body of the torus would be wholly eradicated by the one-two punch of the Meissner effect during the conversion to superconductivity, and the superconductive Diamagnetism of the final object. The combined result is a perfectly superfluid and superconductive black hole torus, completely devoid of any hint of magnetic fields within the torus, yet tightly surrounded by epic magnetic fields, as well as a stabilizing accretion disk on the outside. This recipe of circular stability is what physically prevents the entire structure from a final collapse to the gravitational center, much like the architectural structure of an arch keeps a heavy wall from collapsing a doorway from above, under the weight of gravity.
As a supremely superfluid, superconductive entity, the magnetic field in the center of the torus would have almost unimaginable power. This massive field, deeply hidden inside the center of the torus and aligned perpendicularly to the torus plane, drives the enigmatic plasma jets we observe in many black holes.
When plasma spins off from the inner wall of the torus (most likely because of the accretion of new material via a reconnection/ injection event at the outer wall of the torus), it is immediately accelerated far out into space, via the central magnetic engine. That is how a torus could easily generate the plasma jets we frequently observe, as material migrates from the outer regions of the torus to the inner regions, and, eventually, to the fateful inner wall of the torus at the edge of the central magnetic field. Once material pulses off the inner wall, it is blasted back into space at a high velocity, where the moving plasma creates a secondary, albeit far less powerful magnetic field extending far away from the black hole itself.
While the black hole torus structure is a large step upward from the humble arch in terms of long-term stability, it is not immune to damage or disintegration. There are two primary threats to any black hole’s long-term survival.
One primary threat for all black holes is a lack of new material via the accretion disk, which, over a long enough time span, could eventually result in a large loss of mass via Hawking radiation. A large enough loss would be enough to compromise the structure, resulting in loss of superconductivity and the failure of the torus.
A secondary threat for all black holes is an overabundance of down-falling (and/or up-falling) material. While gravitational fields generated by the accretion disk help to safely herd material toward the plane of the disk, sometimes material does manage to fall directly onto the inner regions of the torus itself from above or below the plane. There, inner magnetic reconnection events would result in the injection of material directly into the open center of the torus, while some material would also be ejected outwardly, at a near-perpendicular angle to the plane of the disk.
A large enough amount of infalling material could conceivably result in high levels of material being pumped into the previously open central region by these magnetic reconnection events. This material, directly subjected to powerful magnetic fields, would not be superconductive. Feasibly, enough injected non-superconductive material might become continuous with the inner wall of the torus before it can be ejected back outward, leading to a patchwork destruction of superconductivity throughout the structure, and the failure of the torus. Essentially, once the hole is filled in, it is all over for the black hole.
Most likely, a torus failure would involve a double-whammy of factors. A lack of incoming material via the accretion disk, combined with an over-abundance of infalling material, would be a very detrimental combination. But does this mean a failed black hole torus would revert to an oblate neutron star state, its “donut hole” now filled in? That does seem like a logical regression. Perhaps a magnetar is the crumpling result of a failed and reverted black hole torus.
It should be noted that the area in the center of the torus is the most hidden to our instruments, and we are not able to peer in there very well. A black hole’s plasma jets have an associated magnetic field, but this would be almost trivial compared to the powerhouse magnetic engine lurking within the central, unseen region within the ring of the torus. Perhaps this highly energized central system, overall, is enough to reduce the number of cosmic rays penetrating the central molecular zone (CMZ) of the Milky Way, as has been recently observed by cosmologists from the Chinese Academy of Sciences.
Someone may fuss over the use of the term “black hole.” It has been part of the lexicon for many years, and it is used in this article, although, with all due apologies to Roger Penrose, the torus black hole would not, and does not, experience total gravitational collapse to the point of a singularity. Even in the most extreme (and least likely) interpretation, the torus must be a two-dimensional object, at the very least. Regardless, the torus does have a central hole, and it is going to be awfully difficult to get a direct look inside of that area, so perhaps the term “black hole” does make sense after all.