Solar Flares and Radio Communications – How Great Are Our Electronics?


On November 8, 2020, the Sun exploded. Well, it’s a bit dramatic (it explodes a lot) – but a particularly large sunspot called AR2781 produced a C5-class solar flare that is also a medium-sized explosion for the Sun. The range of flares ranges from A, B, C, M and X to one zero to nine in each category (or even greater for giant X flashes). So a C5 is about the dead center of the scale. You may not have noticed, but if you lived in Australia or the Indian Ocean and you were using radio frequencies below 10 MHz, you would have noticed that a 20 minute long radio blackout occurs at those frequencies due to the flare.

According to NOAA’s Space Weather Prediction Center, sunspots have the energy to produce M-class flair that is a sequence of being more powerful. NOAA also has a scale for radio interruptions ranging from R1 (an M1 flare) to R5 (an X20 flare). The sunspot under consideration is currently facing the Earth, so any new flare will cause more problems. This led us to ask ourselves: what if there was a major radio interruption?

You think this happens more often. In October, the AR2775 set two C flares and while the flare did not hit the plasma with the Earth, UV radiation caused a brief radio outage in South America. X-rays and UV radiation travel at the same speed as light, so by the time we get a flare, it’s too late to do anything about it, even if we can.

The effects are mostly related to the propagation of radio waves through ions. In the 1700s, who would care? However, in the mid-20th century, a lot of things depended on this property of high frequency radio waves. Today, it may not be nearly as much.

If you own a shortwave radio, you may have noticed that it isn’t as broadcast-wise to listen to as it was decades ago. Broadcasters want to use the Internet to reach an international audience, until now they target a part of the world where the Internet is scarce or restricted. Even the AM radio band is not the mainstay it used to be. Many people listen to FM (which promotes differently), satellite radio, or they stream audio from the Internet. Sure, that uses radio, but not ionospheric diffusion.

Transcontinental transit

Perhaps the biggest commercial users of the radio band are now transoceanic aviation and ships at sea, but still, many of those uses are now using satellites and much higher frequencies. There are still ham radio operators, of course, some time and frequency standard stations such as WWV. While there were some radio frequency navigation systems such as LORAN and Gee, almost all of them have gone in favor of GPS.

Will disbanding these services be a big deal? Probably not, although if you are on a plane or at sea, you may feel a bit stressed. Then again, it just depends on how important the radio device is to you and how many options you have.

Again, really big events – the so-called Carrington events – can directly affect lots of electronics. The insurance industry thinks it could run up to $ 2.6 trillion in losses. Worried? Maybe keep an eye on the Space Weather Channel. If you are interested in what the government of the United States will do if we have another Carrington level event, they have written all of this. Honestly, however, the plan seems to, in essence, make better forecasts and develop new technology. FEMA has an information-graphic claiming that a solar flare can affect your toilet, although it seems like it will take a long time to happen. His excellent but unpublished memos on the subject are a bit more interesting to read. Maps on pages 16 and 17 showing that the power grid is vulnerable to geomagnetic storms is particularly interesting.

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