I have been tasked with measuring both the voltage and current output of a plasma system but have only been provided and oscilloscope to do this (Tektonix TBS 2000 Series 100MHz, 1G/s) and a high voltage probe (Tektronix P5100A, 500MHz, 40Mohm, 2.5pF, 100X:1000V CAT II). The system consists of a variable transformer connected to the main which then has a "Neon Power Supply" connected (Input: 120VAC 50/60Hz 0.9A, Output: 10kv 30mA) leading to the plasma "chamber". I have tried to connect the oscope probe to just the power supply to see the voltage output but receive what can only be described as high pulses of voltage which increase in frequency as I increase the voltage on the transformer. When connected to the plasma "chamber" these pulses in voltage can be seen to cause the plasma to pulse as well.
In order to measure the voltage and current of the system with the use of the oscilloscope how could it be done? I was able to source a handheld DMM (Tektronix DMM157) and have had the idea of building a voltage divider in order to then measure the voltage (using 47, 510kohm resistors as R1 and 3, 430kohm resistors as R2) but I am not entirely to sure how safe this would be especially with such high voltage. Any help is greatly appreciated!