RADIO PULSES FROM EXTENSIVE AIR SHOWERS AS A RESULT OF MOVEMENT OF SLOW ELECTRONS IN ATMOSPHERIC ELECTRIC FIELD

The numbers, energies and lifetimes of slow ionisation electrons produced in the extensive air showers caused by high-energy cosmic-ray primaries are discussed, and it is shown that the electric field in the atmosphere causes these electrons to accelerate to a drift velocity in the direction of the field. A suitably-placed observer experiences this acceleration as a change of electric field, the lifetimes of the electrons and the shower dimensions being such as to make this change of field observable at radio frequencies (~10 MHz). Calculations indicate that this mechanism should be at least as effective as other previously suggested radio emission mechanisms for showers at high zenith angles, although, since the normal fine-weather electric field is essentially vertical, the mechanism is relatively ineffective for showers from near the Zenith. © 1968.