This is my favorite version, which I think ultimately is just POPS on steroids:drmike wrote:Good things to think about, and I better get some models running.....
1) Injection energies for B11 and p are set so E_sub_p = 11*E_sub_b11 when everything reaches the center. (If you think about this for a minute, you'll notice that makes the scalar momenta of both populations equal. For a 550 keV center of mass, this comes out to be 45,800 eV for the B11 and 504,200 eV for the protons.)
2) You "sputter" ions into the system in bundles that are very thin radially. No need to worry about distributing them; in fact, you might do best by having the B11 injector directly opposite the p injector.
3) If you can guarantee that there is only one B11 ion group and it arrives at the center only when the single p ion group does (and, since they have different energies, this is not a slam-dunk), then the only collisional scattering you'll get (mod brem, which I'm going to ignore for right now), is pure radial scattering. Since the momenta are equal in both populations, and since you only get ion-ion collisions at the center, all ions retain the same momentum and therefore don't energy-spread very much, if at all.
4) Note that scattering will spread the ion bundles into spherical shells over time. Moreover, I think that if you pulse new bundles of ions into the system as the shell reaches its maximum radius, you can a) replace ions that have fused and b) pump up the density to any desired value.
Notice how POPS-like this is. However, instead of trying to pump the ions together with RF, you create the population with stupid injection tricks.
The fly in the ointment is figuring out whether you can have bi-energetic populations that are constrained to have both the proper energy differences and identical travel times from injection to center. I'm trying--so far unsuccessfully--to model this.