Aurora Borealis

Auroral displays are natures multi-gigawatt plasma globe. There is a multitude of reasons I find them fascinating. The aspect that probably holds the greatest fascination for me is that they are prominently featured in many of my dreams involving the future.

Their complexity exposes the complexity of the interaction between the earth’s magnetic field, the solar wind, and the upper atmosphere.

I am fascinated by the anecdotal reports I’ve read ranging from descriptions of aurora related events, particularly descriptions of auroras at tree top levels or reaching the ground such as describe here, and by descriptions of sounds accompanying an aurora such as described here. Take a look at this page concerning auroras.

The reports of sounds associated with auroras are so numerous that it’s impossible to believe people do not experience this, however I am not sure that the sounds are acoustic in nature. The reason I make this conjecture is because nobody has succeeded in recording these sounds acoustically, although they can be recorded using VLF receiving equipment which records audio frequencies of electromagnetic waves. Also, the sounds are usually perceived as being in step with the lights although the distances involved would require minutes for the sound to transverse if it were acoustic in nature.

I have personally had the experience of hearing lightning strikes instantly. That is, I have heard crackling noises at the exact time I see the lightning strike followed later by thunder. When I experience this I hear the crackling at the exact same time I see the lightning flash. I do not know the nature of this phenomena but I suspect it is the same mechanism by which people hear auroras.

I’ve heard about something some people experienced on a polar air flight. During the flight, everything became charged as with static electricity, hair stood up on end, people smelled ozone, some felt ill. Following the flight they had what resembled sunburn.

I’ve seen auroral displays here in the greater Seattle area half a dozen times and each time they’ve been substantially qualitatively different and I am very puzzled by some of the phenomena I’ve seen displayed in auroral displays.

I have seen the classic greenish curtains and red kind of blob displays that are so commonly shown in photographs from higher latitudes. It is not difficult for me to visualize the physics involved in these displays, charged particles following the earth’s magnetic lines interacting with molecules in the upper atmosphere.

I have seen a display where there is a white narrow rope of light stretching across the sky that appears very thin, like a neon tube, and it moves, wriggles, and drifts. When I saw this display it lasted only about ten minutes. I have never seen a photograph of a display like this. The other night my wife saw a very similar display. It was bright enough to be seen even with an almost full moon in the sky. I do not understand what possible configuration of magnetic field lines and solar wind could produce such a display. I am very curious as to how this plasma could be confined to such a narrow path across the sky.

Another display that I saw was accompanied by the green curtain and red blob type of displays farther north, but immediately over our location it appeared as if someone had taken a giant point source of light, shined it on the ocean, and then the wave pattern reflected upon a giant projection screen in the sky. The waves moved in real time as waves in water do. The enormity of this display was overwhelming. I would like to understand the basis for these wave patterns and motions.

Auroras have affected telegraph lines in the past, inducing currents in the lines first of one polarity, and then of the reverse polarity. Take a look at these accounts.

One aspect of auroras that does puzzle me, I went the first three decades of my life without having seen one in this area, in spite of the fact that when I was younger I usually slept outside during the summer in a sleeping back looking up at the sky and stars before falling asleep, yet, in the last decade I’ve seen them on half a dozen occasions now.

I am wondering if this increase is just the result of an unusually active solar cycle (and the next is predicted to be even more active) or if there are other factors.

As I mentioned, I’ve had these dreams that often feature very intense auroras. In these dreams I see auroras that are so intense that they are visible during dusk and dawn. Also in these dreams they seem to be visible most often about 1-2 hours after sunset or before sunrise, this is different than the current pattern which tends to have them be strongest between about 11pm-3am.

I’ve also noticed changes in radio propagation lately. I have a shortwave receiver that covers pretty much from about 3 Mhz up to 30 Mhz. Those of you familiar with shortwave propagation will know about the term “maximum usable frequency”. The higher the radio frequency, the less it is refracted by the ionosphere back to the earth. At any given time, above some frequency the radio waves can not be refracted back. The highest frequency that can be refracted back is known as the maximum usable frequency.

This frequency varies with the degree of ionization in the ionosphere. That in turn varies with the level of solar activity. The higher the solar activity, the higher the ionization and by extension, the higher the maximum usable frequency. Higher levels of ionization also cause higher levels of absorption at lower frequencies and so high solar activity ruins radio propagation at lower frequencies.

The ionization is much stronger on the day side of the earth since it is receiving ultraviolet and other solar radiation that ionizes the upper atmosphere. There is also, for reasons I do not understand, seasonal variation, and summer months see stronger ionization and a higher maximum usable frequency. This might be because the solar radiation is more direct on and not at an obtuse angle, really I do not know. It is interesting that auroral activity is actually strongest in the spring and fall but this is not the time of the strongest ionization of the ionosphere.

When I was younger, with the exception of peak solar activity years, it would be rare to see significant shortwave propagation above about 18 Mhz in the daytime and 9 Mhz at night during the summer. During the winter months, even daytime propagation often didn’t get much about 10 Mhz.

I also used to do television DXing, this most often when the maximum usable frequency got high enough to propagate television frequencies. When I first got interested in this hobby, it was something that would “open up” maybe several times a year, usually during the late summer months and early afternoon time frame, usually only affecting channels 2 and 3, the lowest channels on the VHF television bands in the United States (some other countries have a channel 1 at 45 Mhz).

In recent years however, even in the winter I am frequently seeing the maximum usable frequency go up to 21 Mhz, occasionally up at 28 Mhz which is about the highest frequency I can generally receive anything on my shortwave receiver. Even at night I am seeing the maximum usable frequency still often around 15 Mhz.

At the same time I’ve been seeing these increases in high frequency propagation, I’ve noticed that night time propagation on the AM broadcast band seems to be very poor compared to what it used to be and even day time propagation over paths of a hundred miles or so seems substantially degraded.

I used to be able to receive CKLG 730 and CFUN 1410 from Vancouver BC quite well here in Shoreline, now they are both marginal under the best of conditions. I’ve also heard ham operators that like to work the 80 meter and 160 meter ham bands complain about poor propagation on those frequencies (about 3.6 Mhz and 1.8 Mhz respectively).

In the summer, television skip has become common, and I have seen it active all the way up to channel 12, (and we have a local station on 13) one occasion, and up to channel 6 and into the FM band on multiple occasions, and I have seen channel 2 and 3 active frequently, almost daily in late July and early August. I have also seen openings on these frequencies at night.

The increase in my observation of aurora phenomena and of high frequency radio propagation may be related to solar activity or to changes in the earth. The sun has been unusually active recently, but at the same time the earth’s magnetic field has been weakening and minor magnetic poles strengthening. This may be allowing more of the solar wind to interact with the earth’s atmosphere. I also wonder how the increasing amount of CO2 in the atmosphere affects things. It’s a very small percentage of the atmosphere still, but perhaps it has a significant effect on the electrical properties of the atmosphere even at low concentrations.

I know that some gases ionize very easily, argon for example, a relatively low voltage will produce long arcs in argon at atmospheric pressures, but even a small amount of nitrogen will stop those long arcs, so a very small percentage of one gas can greatly impact the electrical characteristics of the mixture.

I am curious if anyone else has seen the “neon tube” type of auroral display that I described earlier? It’s really difficult for me to envision any configuration of magnetic field lines that can account for this type of display.

The “water wave” display that I saw, seemed positively organic. This might seem really far-fetched, but I wonder if the increasing population of the earth is not perhaps directly responsible for the increase in these phenomena, if it doesn’t some how relate to the life force, qi, orgone energy, whatever label you might like to give it.

I’d be very interested in hearing from anyone with reports of anomalous aurora sightings (down to the ground, hearing them, radiation burns, etc), or radio conditions, or other anomalous geophysical phenomena.

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