## Single-stage acceleration mechanisms operate very far from equilibrium. They therefore have a huge difference in entropy between W and Q, and are therefore inherently inefficient. Likewise environmental conditions are far from equilibrium, and are thus inherently unlikely. The product of these two situations = low density of accelerated particles.

**Energy Source * Efficiency * Probability = Power**## A trap allows small impulses to be cumulative. The pulses are close to equilibrium and are also likely. Thus a trap = higher density of accelerated particles.