chokes with ferrite cores, $\pm 5$% tolerance, and 31 $\Omega$ or less DC resistance. These inductors were installed in one of two clear plastic tubes, each with a slot for the leads that was later sealed with room-temperature-vulcanizing (RTV) silicone, and the inductors were immersed in mineral oil.

The load inductor $L_\text{s}$ was a close-wound single-layer solenoid made from a 55.4 cm varnished winding of approximately 791 turns of 22 awg magnet wire on a plastic pipe with an outer diameter of 8.8 cm. The measured inductance was 8.07 $\pm$ 0.03 mH at 10 kHz, and DC resistance was 11.8 $\pm$ 0.1 $\Omega$. The estimated effective Medhurst self-capacitance[@lee] is $\sim$ 8 pF. Note that coupling is expected between the load and stage inductors as installed. This coupling could be suppressed with different physical arrangements, or by using different winding patterns.[@FieldContainingInductors] Alternatively, the load and stage inductors need not be separate components.

The solenoid base current was measured using a Pulse F15155NL current transformer with a 1 k$\Omega$ shunt resistor, which gave a sensitivity of 2 V/A over 0.5–700 kHz. The bandwidth limitations of the current transformer led to the initial measurement error in Fig. 3(b), and of a capacitive-pickup probe 