Low Frequency Radio Emission from Extensive Air Showers

Abstract

THE observed radio emission from extensive air showers at frequencies between 30 and 100 MHz is in good agreement with theory¹. Both the typical field strength per unit bandwidth, ε ν, and the lateral distribution of the radiation about the shower axis can be given a quantitative interpretation. At lower frequencies the situation is much less satisfactory. Theory predicts that ε ν should rise smoothly from zero at ν=0 towards the observed values at 30 to 100 MHz, but the experimental values between 2 and 5 MHz are about 100 times larger^2–5. The calculation presented here is intended to set a generous upper limit to ε ν based on the least controversial elements of the theory. Because the claimed experimental values are greater even than this upper limit, I suggest that further checks are needed.