Pacemakers and lightning bolts

[apchar]

I'm working on a lightning bolt experiment at U of Washington to see how carbon composite materials hold up when hit by lightning. We have as much as a 40 kV 80 kA 50 us arc across a <1cm gap from a copper/tungsten electrode to a plate of carbon composite connected to ground. I know this must put out one heck of an Electro-Magnetic Pulse (EMP) and I'm worried about someone walking by with a pacemaker and dropping dead when we fire this thing. I need to characterize the electric field strength of the EMP a few meters away.
Is it a simple matter of putting up a 1 meter dipole connected to a scope and measuring the voltage (E in V/m = V_measured / 1 meter)? That sounds too easy to be right.

Apchar

 

[berkeman]

I'm working on a lightning bolt experiment at U of Washington to see how carbon composite materials hold up when hit by lightning. We have as much as a 40 kV 80 kA 50 us arc across a <1cm gap from a copper/tungsten electrode to a plate of carbon composite connected to ground. I know this must put out one heck of an Electro-Magnetic Pulse (EMP) and I'm worried about someone walking by with a pacemaker and dropping dead when we fire this thing. I need to characterize the electric field strength of the EMP a few meters away.
Is it a simple matter of putting up a 1 meter dipole connected to a scope and measuring the voltage (E in V/m = V_measured / 1 meter)? That sounds too easy to be right.

Apchar

Welcome to the PF, Apchar. There are several things to be addressed in your post. First, I hope you are doing this work in a shielded area. You are not allowed to be transmitting EMP or other RF energy into the atmosphere. The FCC can get cranky when you do that. This should only be done in a shielded area (indoors or out). And you can put warning signs on the entrances to the shielded area warning pacemaker wearers not to enter.

And measuring the field strength is not simple, because of the broadband nature of an arc like that. It will be putting out RF energy across a broad spectrum, so you would need to use a broadband antenna (like a bicon) to try to pick up the representative time-domain waveforms.

 

[Naty1]

Interesting issue..makes me wonder if anybody with a pacemaker has ever been affected by lightning strikes in the area...