In late August of 2001 Chris and Kim started construction of the next iteration of Project Thumper, the Mk-2 Prototype.

The same manner of stacked washer/split cable connections that Mark invented were used on the second prototype as well.

We also used a great deal of tie-wraps. we quickly learned just how powerful the electromagnetic repulsion forces are between the two main rails when it discharged and cleared the table by whipping the output rails loose.

We had to make a new set of rails when we decided to add another pair of banks (bringing the total to 80 caps) because the first rails were for 40 caps max and the output currents required something far more substantial than just 6AWG. We cut another pair of 500MCM rails for the full length and rebuilt the connections with several dozen more tie-wraps. Thankfully they were donated or we'd have spent a years budget on tie-wraps. alone, we went through hundreds of them with this project.

Here you can see the temporary charging circuit we kludged together from parts of the old MV-4 power supply cabinet.

You can't get much simpler than that for a charging system. Big plug, big diode, and a dream.

It's a miracle we survived past this stage.

Some safety systems were already in place though. Here you can see the safety jumper shorting out the main rails.

We also developed a new metric for measuring the progress with the array. Since we lacked any manner of serious high-power probes, instrumentation, or even a decent oscilloscope we had to get creative and come up with something on a budget.

Pop cans work well. We measured the success of the array by the level of damage it would do to a generic pop can placed across it's output rails.

The finished Mark-2 Prototype