Hm. It reads to me like the basic problem, as Jimmy T says, might be rejection/reverse acceleration of the slow ions by the surge of induced EM fields in the Rogowski coil from the faster ions. That suggests to me a staged system, with each stage having inductance low enough to accommodate the slower ions, which (somehow) would then be neutralized and collected while a “kink” in the tube then receives the faster ones. A deflection field could perhaps be tuned to be strong enough to deposit the energy-drained slowest/stopped ions in a collector, but only to “bend” the remaining energetic ones into the next leg of the coil.
That the slowest ones, by definition, arrive later will help. It would permit the planning of stages to position collection-deflectors in the most convenient manner, as the fastest ions will transit the entire sequence before being stopped, followed by the next “cadre” which would enter the second-last catchment, and so on. Each group has its own spread or range within it, so how much of a problem that is would determine how finely divided the coil would have to be into stages.
Whether all that is possible, I don’t know.
