Letter | Published:

Hydromagnetic Emissions at the Geomagnetic Poles

Nature volume 212, pages 170171 (08 October 1966) | Download Citation



MAGNETIC micro-pulsations of regular appearance in the frequency range 0.2–5 c/s have been studied intensively in recent years. Some of the very regular events show an envelope on an amplitude–time trace that resembles a string of pearls. They have been variously called pearls, Pc 1, hydromagnetic whistlers or hydromagnetic emissions. If these micropulsations are recorded on slowly moving magnetic tape and spectrally analysed with a ‘Sonagraph’ or ‘Rayspan’, using the speed-up technique, the emissions often display distinct structural elements. There are usually repeated series of individual emissions the frequencies of which appear to rise or fall rapidly with time as those shown in the frequency–amplitude–time displays (sonagrams) of Fig. 1.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1.

    , J. Geophys. Res., 70, 1069 (1965).

  2. 2.

    , , , and , J. Geophys. Res., 71, 1492 (1966).

  3. 3.

    , and , J. Geophys. Res., 71, 1499 (1966).

Download references

Author information


  1. Geophysical Institute, University of Alaska, College, Alaska.

    • E. M. WESCOTT
    •  & V. P. HESSLER
  2. Boeing Scientific Research Laboratories, Seattle, Washington.

    • J. F. KENNEY


  1. Search for E. M. WESCOTT in:

  2. Search for V. P. HESSLER in:

  3. Search for J. F. KENNEY in:

About this article

Publication history




Further reading


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.