Home » hum research » Technical reference for possible interactions between solar activity and the Worldwide Hum

Technical reference for possible interactions between solar activity and the Worldwide Hum

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The original source is listed just below; I’ve pasted the abstract below that. This is not light reading; let me know if you need help translating this or if you are interested in full-text access.


  1. Effect of solar flares flux on the propagation and modal composition of VLF signal in the lower ionosphere

    NASA Astrophysics Data System (ADS)

    Bouderba, Yasmina; Nait Amor, Samir; Tribeche, Mouloud


    The VLF radio waves propagating in the Earth-Ionosphere waveguide are sensitive to the ionospheric disturbances due to X rays solar flux. In order to understand the VLF signal response to the solar flares, the LWPC code is used to simulate the signal perturbation parameters (amplitude and phase) at fixed solar zenith angle. In this work, we used the NRK-Algiers signal data and the study was done for different flares classes. The results show that the perturbed parameters increase with the increasing solar flares flux. This increases is due to the growth of the electron density resulting from the changes of the Wait’s parameters. However, the behavior of the perturbation parameters as function of distance shows different forms of signal perturbations. It was also observed that the null points move towards the transmitter location when the flare flux increases which is related to the modal composition of the propagating signal. Effectively, for a given mode, the plot of the attenuation coefficient as function of the flare flux shows a decreases when the flux increases which is more significant for high modes. Thus, the solar flares effect is to amplify the VLF signal by reducing the attenuation coefficient.



  1. jimvandamme says:

    Um, either this is a broken link, or this just points to the portal of the whole Digital Library for Physics and Astronomy. Or you’re just being a tease.

  2. Jamie says:

    It started again on Sunday evening. Not as loud as the period over New Year but still audible. By the way I recorded my location and questionnaire before Christmas but it hasn’t been uploaded on to the map yet. Any reason?

    • The map upload process is very tedious because I must manually inspect every report,and this can require quite a few hours. That’s why I only upload once every few months. There’s a previous post on this blog on that topic.

  3. Jamie says:

    Ah ok. Thanks Glen. By the way, the BBC have just done a feature on the phenomena

    • Yes, apparently the (original) Bristol Hum is back. We’ve come full circle.

      • Jonathan says:

        Yes Glen, I can confirm that the hum is back in the Bristol area. In fact, only yesterday I thought the hum had been switched off as I couldn’t hear it. But that idea was shattered as it returned in the evening and is in full swing today. I perceive it as being to the right side of my head and whist I am typing is a continuous tone around 110Hz. Usually, the frequency is lower than this and the texture of the sound may be different such a constant rumbling or low frequency wind-type noise. I sometimes hear a sound that resembles a whining that on a keyboard relates to the A or B flat octave above middle C ( around 800 to 900 Hz). I also hear a lot of white noise effects which may occur in different pitch bands. These sounds are the most annoying as they are enough to drive a person crazy but I try to resist them as much as possible to keep my sanity.

  4. frank rizzo says:

    this hum always seems to be the loudest when its a full moon. Has anyone else noticed this? Tonight is off-the-charts aweful too!

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