Simulate magnetic field caused by a lightning strike - CST

I would like to simulate the magnetic field at approx. 1m from a copper drain pipe (mounted vertically onto the wall of a house), caused by a lightning strike.
Does anyone have experience with setting up such simulation?

To simulate a lightning bolt, it is about the same as a wire carrying so many hundreds or thousands of Amperes. The bolt itself is a few inches wide.
I've read the normal direction of electron flow is from ground to cloud, but occasionally it is the reverse.
I've read duration is a tiny fraction of a second. However I've heard static bursts on the radio that sound like several crackles in a row, lasting as long as 1/4 second total.