Rectangular wave, extraction of ions from a stopping cell

[Cocoleia]

Hello. I'm not sure if this question is to project-specific, but I will try to explain as best that I can.

I am working with a system such as this one, with only a few differences: http://www.sciencedirect.com/science/article/pii/S0168583X1400706X
it is a cryogenic stopping cell. The part I am running simulations on is the RF carpet. The current carpet configuration uses a sinusoidal wave for the RF amplitude. I am running simulations on a carpet that would use a rectangular wave, with 4 electrodes. I can change the frequency of these electrodes.
I set the phase shifts to 0, 180, 0, 180 over the electrodes. I was testing different phase shifts, and now I am testing this one.
In principle, I test to see how many ions can get extracted from the system (transmission efficiency)
When I test this rectangular wave with a frequency of 1MHz, it takes an RF Amplitude of 76V to get 100% transmission efficiency. When I test it with 3MHz, it only takes 14V to get 100% transmission efficiency.

What would explain why a higher frequency requires a lower voltage for ion extraction?
I hope this was well explained. let me know if there are more explanations needed.

 

[LightHero]

The higher frequency of the rectangular wave allows it to be more easily tuned to the resonance frequencies of the ions in the system. This means that the ions receive more energy per cycle of the wave, so less voltage is required to extract them from the cell. Additionally, the higher frequency allows for more rapid changes in the electric field strength, so the ions do not have as much time to lose energy within the cell before being ejected.