Fig. 8: Trap loading and survival of H⁻ against current in the trap magnet.

The data is shown as gray stars, representing individual realizations, and the blue dots are the average of the gray stars values for the corresponding current. Two models are shown. The purple line represents a simple axial 1D model concerning only the (harmonic) axial and cyclotron frequencies relation for stability. The red lines guide the eyes through the results of a Monte-Carlo model considering the entrance aperture of trap region, at magnetic fields much lower (\(\sim\)1/13) than in the trap, and the survival of the particles in the trap given its diameter for different radial energy distributions. The axial energy distribution is taken as an exponential decay as in Fig. 5 and the transverse energy distributions are taken as exponential decays but with different energy scales. In the continuous, dashed, and dotted red lines the ratio of the transverse to the axial energy scales input trial to the simulation is \(\eta\) = 1/12, 2, and 20, respectively, while the trapped sample ends with the \(\eta\)’s shown in the figure. Magnetic mirroring effects are taken into effect in the energy rescaling between the trap entrance aperture to the trap center. The models do not include a full particle tracing but only consider the particles at the entrance aperture and the trap center. The error bars from the simulation represent one standard deviation for the 50 realizations. See section Results and Methods for further discussion.