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Transmission of Electromagnetic Pulse into the Head

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James C. Lin, Chuan-Lin Wu, C. K. Lam · 1975

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Electromagnetic pulses penetrate the head and change shape, with peak effects at the brain surface.

Plain English Summary

Summary written for general audiences

This 1975 study examined how electromagnetic pulses penetrate human and animal head models using mathematical modeling. Researchers found that electromagnetic pulses change shape as they enter the head, with the transmitted pulse being proportional to the rate of change of the original pulse. The peak effects occurred at the surface where the pulse first enters the head.

Why This Matters

This foundational research from 1975 demonstrates a crucial principle: electromagnetic energy doesn't just bounce off our heads-it penetrates and transforms as it enters brain tissue. The finding that transmitted pulses are proportional to the rate of change of incident pulses reveals why pulsed EMF sources (like cell phones that transmit in bursts) may have different biological effects than continuous wave sources. What makes this particularly relevant today is that modern wireless devices operate using pulsed signals, not steady waves. The study's focus on pulse transmission characteristics helps explain why the biological effects of EMF aren't simply about power levels, but also about how quickly those power levels change. This research laid groundwork for understanding that the brain doesn't experience EMF the same way it exists in free space-the electromagnetic environment inside your head is fundamentally different from what's measured outside it.

Original Figures

Diagrams extracted from the original research document.

Page 1 - Fig. 1 depicts a typical electromagnetic pulse waveform.
Page 2 - Fig. 2: Transmitted EMP inside a 10-cm-radius sphere representing an adult human size head.

Exposure Information

Specific exposure levels were not quantified in this study.

Cite This Study
James C. Lin, Chuan-Lin Wu, C. K. Lam (1975). Transmission of Electromagnetic Pulse into the Head.
Show BibTeX
@article{transmission_of_electromagnetic_pulse_into_the_head_g4340,
  author = {James C. Lin and Chuan-Lin Wu and C. K. Lam},
  title = {Transmission of Electromagnetic Pulse into the Head},
  year = {1975},
  
  
}

Quick Questions About This Study

The transmitted pulse becomes proportional to the time rate of change of the incident pulse, meaning the pulse shape transforms as it penetrates brain tissue rather than maintaining its original form.
Peak effects occur at the leading surface of the head where the electromagnetic pulse first enters, suggesting the outer brain regions experience the highest initial electromagnetic field intensities.
Researchers used a triple exponential function to describe incident pulse waveforms, which showed close agreement with actual measured electromagnetic pulse shapes in laboratory testing.
The research used homogeneous spherical models of human and animal heads rather than actual biological tissue, allowing mathematical analysis of electromagnetic pulse transmission characteristics.
The proportional relationship to time rate of change means rapidly changing electromagnetic pulses create different biological exposure patterns than steady fields, explaining why pulsed EMF sources may have unique effects.