Pacemakers and lightning bolts

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SUMMARY

The forum discussion centers on a lightning bolt experiment at the University of Washington, where researchers are testing carbon composite materials against a 40 kV, 80 kA, 50 µs arc. Concerns arise regarding the potential Electro-Magnetic Pulse (EMP) generated by this experiment, particularly its effects on individuals with pacemakers nearby. It is established that measuring the electric field strength of the EMP is complex due to its broadband nature, necessitating the use of a broadband antenna, such as a biconical antenna, rather than a simple dipole setup.

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  • Understanding of Electro-Magnetic Pulse (EMP) phenomena
  • Knowledge of RF energy and its regulatory implications (FCC guidelines)
  • Familiarity with broadband antennas, specifically biconical antennas
  • Basic principles of electric field measurement and safety protocols for experiments
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  • Research the use of biconical antennas for measuring broadband RF signals
  • Study FCC regulations regarding EMP and RF energy emissions
  • Investigate safety measures for conducting experiments involving high-voltage arcs
  • Explore the effects of EMP on medical devices, particularly pacemakers
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apchar
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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
 
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apchar said:
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.
 
Interesting issue..makes me wonder if anybody with a pacemaker has ever been affected by lightning strikes in the area...