Gravitoelectromagnetism higher-order effects See http://en.wikipedia.org/wiki/Gravitoelectromagnetism#Higher-order_effects
According to the Higher-order effects...
"Gravitomagnetic arguments also predict that a flexible or fluid toroidal mass undergoing minor axis rotational acceleration (accelerating "smoke ring" rotation) will tend to pull matter through the throat (a case of rotational frame dragging, acting through the throat). In theory, this configuration might be used for accelerating objects (through the throat) without such objects experiencing any g-forces."
Questions:


*

*If I am able to produce a toroidal mass of plasma undergoing minor axis rotational acceleration, then I could accelerate objects (through the throat) without such objects experiencing any g-forces?

*Are there any instances or citations/references of research where someone has shown to be able to create, maintain, and accelerate a spinning toroidal mass undergoing minor axis and major axis rotational acceleration?


I have worked on a personal project where I have been able to create and accelerate a toroidal mass that undergoes acceleration of the minor axis and major axis.
This may be a good use for such a thing.
 A: To 1.:
You don't need a plasma for this effect. As the article states this 'pulling through the hole effect' is a frame-dragging effect.
The apparent force (seen in the Lab-frame) results from the object falling along the spacetime-geometry, however in its own frame there are no g-forces as a free fall is always force-free. So the statement you put in bold text is nothing special.
All this is purely gravitational. I get the impression that you think here are interactions of gravity and electromagnetism at work (hence your idea with the plasma). However as the wikipedia-article clearly states, this is not so, as Gravitoelectromagnetism is "[...] (an) approximate reformulation of gravitation as described by general relativity in the weak field limit".
Therefore this is one of many approximations theoretical phycisists use to make the nonlinear equations tractable and easier solvable for a given set of problems.
To get a feeling how small this would be take for example gravitational measurment satellites like GRACE and Gravity-Probe-B. While the former failed to, the latter achieve to measure the frame-dragging effect induced by earth. The frame-dragging by the torus will be now at least a factor $m_{earth}/m_{torus}$ weaker than that, or even the squared of this quantity, as its higher order.
Therefore the actual force on the mass you want to accelerate through the torus will be unmeasurably small.
I think this relates to part 2. of your question. Ofc maybe you're able to create such an accelerated torus (smoke rings are an example of that). But you won't be able to accelerate objects through the mouth. Even simple air-drag will be much stronger than the frame-drag.
A: I'm afraid I can't answer either question, but can I point out that a torus with a major and minor rotation is arguably emulating a Dirac bispinor, and could be useful for something other than gravitomagnetism. Note that Thomson and Tait contrived smoke rings in an early theory, and demonstrated attraction and repulsion and annihilation, see http://zapatopi.net/kelvin/papers/on_vortex_atoms.html and "On Vortex Particles" by David St John. 
