How to obtain a high-current AC power source with adjustable frequency?

I’m trying to investigate how the frequency of the alternating current in the solenoid affects the ring motion for a Thomson Jumping Ring apparatus. I have a variable frequency AC power source that outputs a peak voltage of 20V, which is not enough to power my experiment, especially since the power source has an internal resistance of 50 ohms, which means that the current passing through the solenoid won’t be very high. Is there a way I could increase the output current?

I was also considering using a higher voltage AC power source, like a VARIAC or just line voltage, but I haven’t found a way to alter the frequency for these. I tried to get a variable frequency drive but there were none available with a single-phase output.

Any ideas or advice would be very much appreciated.