Experiments like the ones you describe are exactly how we know the reaction cross sections and reaction rates–the chance that a proton of energy x will cause a fusion reaction. Nuclear physics is not at the point these rates can be calculated–they are measured. The maximum probability occurs at energy of around 600 keV. But at much lower energies, which FF-1 has already obtained, we can release enough energy to heat the plasmoid up to 600 keV or even hotter.
