Observation of Radio Pulses from Extensive Air Showers at 3.6 MHz

Abstract

OBSERVATIONS of radio emission from extensive air showers below 20 MHz are difficult to interpret because terrestrial noise, reflected from the ionosphere, is large compared with the magnitude of the radio pulses1. At frequencies below 4 MHz, however, D layer absorption during daylight hours may sufficiently decrease the noise background to enable observation of the radio emission to be made. Results of a preliminary experiment at 3.6 MHz by Prescott et al.1 gave a field strength of 0.5 µV m−1 MHz−1 for showers of size ~ 5×105 particles. In this analysis the noise and signal were subtracted linearly; correct quadratic subtraction yields a field strength estimate of ~1.5 µV m−1 MHz−1. Two further observations of radio emission have been made at low frequencies. Allan et al.2 at 2 MHz, found a field strength of ~750 µV m−1 MHz−1 for showers of primary energy Ep1017 eV. Stubbs3, also at 2 MHz, found a field strength of ~1 µV m−1 MHz−1 for showers >2×1014 eV.

References

  1. 1

    Prescott, J. R., Hough, J. H., and Pidcock, J. K., Proc. Eleventh IUPAP Conf. on Cosmic Rays, Budapest, Acta Physica Hungarica, 29, Suppl. 3, 717 (1970).

    ADS  Google Scholar 

  2. 2

    Allan, H. R., Clay, R. W., and Jones, J. K., Nature, 224, 253 (1970).

    ADS  Article  Google Scholar 

  3. 3

    Stubbs, T. J., Nature Physical Science, 230, 172 (1971).

    ADS  Article  Google Scholar 

  4. 4

    Jasik, H., (ed.), Antenna Engineering Handbook (McGraw-Hill, New York, 1961); Hansen, R. C. (ed.), Microwave Scanning Antennas, 2 (Academic Press, New York, 1966).

  5. 5

    Hough, J. H., and Prescott, J. R., Nature, 227, 590 (1970).

    ADS  Article  Google Scholar 

  6. 6

    Hough, J. H., and Prescott, J. R., Proc. Sixth Interamerican Seminar on Cosmic Rays, La Paz, 2, 527 (1970).

    ADS  Google Scholar 

  7. 7

    Allan, H. R., Clay, R. W., and Jones, J. K., Nature, 227, 1116 (1970).

    ADS  Article  Google Scholar 

  8. 8

    Clay, R. W., thesis, Univ. London (1970).

  9. 9

    Thielheim, K. O., and Beiersdorf, R., J. Phys., A., 3, 79 (1970).

    ADS  Google Scholar 

Download references

Author information

Affiliations

Authors

Rights and permissions

Reprints and Permissions

About this article

Cite this article

HOUGH, J., PRESCOTT, J. & CLAY, R. Observation of Radio Pulses from Extensive Air Showers at 3.6 MHz. Nature Physical Science 232, 14–15 (1971). https://doi.org/10.1038/physci232014a0

Download citation

Further reading

Search

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing