Whistling Radio

You guys should be glad that you are listening to FM radio. Tune in to short wave, if you don't believe.

There is a huge amount of whistles and screeches and unbearable noise.

And no wonder. Our sun is very active now, sending out particles, mostly charged...

They come and hit against the magnetic field causing magnetic storms on  the earth's field and change directions themselves. Some of them come in through the poles and get trapped in the magnetic field. And soon the ionosphere swells up in response. Moving a few miles closer to the earth's surface.

Since short wave radio depends on reflection of the radio waves from the ionosphere, and the ionosphere is changing, reception becomes problematic.

Besides, the trapped electrons are sometimes accelerated by the changing magnetic field lines of earth, leading to emission of radio waves. And that is what we hear as screeching and whistling noises in short wave bandwidths.

By the way, the sun is at its peak activity and is expected to change its north south magnetic orientation. Flipping of the field takes place every 22 years or so. Wait for more in the coming posts.

And for an interesting report on the acceleration of particles in the van Allen belts, high up in the earth's atmosphere, take a look at the recent paper in Science Magazine.

Science 341, 991- 994 (2013); DOI: 10.1126/science.1237743