Pentagon Report Investigated Lasers that put Voices in Head

[American Dream]

February 18, 2008

Pentagon Report Investigated Lasers that put Voices in your Head
by Lisa Zyga

A recently unclassified report from the Pentagon from 1998 has revealed an investigation into using laser beams for a few intriguing potential methods of non-lethal torture. Some of the applications the report investigated include putting voices in people's heads, using lasers to trigger uncontrolled neuron firing, and slowly heating the human body to a point of feverish confusion - all from hundreds of meters away.

A US citizen requested access to the document, entitled "Bioeffects of Selected Non-Lethal Weapons," under the Freedom of Information Act a little over a year ago. There is no evidence that any of the technologies mentioned in the 10-year-old report have been developed since the time it was written.

The report explained several types of non-lethal laser applications, including microwave hearing, disrupted neural control, and microwave heating. For the first type, short pulses of RF energy (2450 MHz) can generate a pressure wave in solids and liquids. When exposed to pulsed RF energy, humans experience the immediate sensation of "microwave hearing" - sounds that may include buzzing, ticking, hissing, or knocking that originate within the head.

Studies with guinea pigs and cats suggest that the mechanism responsible for the phenomenon is thermoelastic expansion. Exposure to the RF pulses doesn´t cause any permanent effects, as all effects cease almost immediately after exposure ceases. As the report explains, tuning microwave hearing could enable communicating with individuals from a distance of up to several hundred meters.

"The phenomenon is tunable in that the characteristic sounds and intensities of those sounds depend on the characteristics of the RF energy as delivered," the report explains. "Because the frequency of the sound heard is dependent on the pulse characteristics of the RF energy, it seems possible that this technology could be developed to the point where words could be transmitted to be heard like the spoken word, except that it could only be heard within a person´s head. In one experiment, communication of the words from one to ten using ´speech modulated´ microwave energy was successfully demonstrated. Microphones next to the person experiencing the voice could not pick up these sounds. Additional development of this would open up a wide range of possibilities."

The report predicts that communicating at longer distances would be possible with larger equipment, while shorter range signals could be generated with portable equipment. Putting voices in people´s heads could cause what the report calls "psychologically devastating" effects. The technology might even allow for communicating with an individual hostage surrounded by captors, although this would require "extreme directional specificity."

With another weapon, electromagnetic pulses could be used to disrupt the brain´s functioning, although this technology was still in the theoretical stages at the time.

Under normal conditions, all brain structures function with specific rhythmic activity depending on incoming sensory information. Sometimes, the brain synchronizes neuronal activity in order to focus on a specific task, but the degree of neuronal synchronization is highly controlled. However, under certain conditions (such as physical stress or heat stroke), more areas of the brain can fire in a highly synchronized manner, and may begin firing uncontrollably.

The report describes a method for replicating this highly synchronized neuron firing across distances of several hundred meters. High-voltage (100 kV/m) electromagnetic pulses lasting for one nanosecond could trigger neurons to fire, disrupting the body´s controlled firing activity. Short-term effects may include loss of consciousness, muscle spasms, muscle weakness, and seizures lasting for a couple minutes. These high-voltage pulsed sources, which would require an estimated frequency of 15 Hz, exist today.

Another form of non-lethal torture described in the report is microwave heating. By raising the temperature of the body to 41°C (105.8°F), humans can experience sensations such as memory loss and disorientation, and exhibit reduced aggression. According to the report, humans can survive temperatures up to 42°C (107.6°F), at which time prolonged exposure can result in permanent brain damage or death.

The microwave heating technique was tested on a Rhesus monkey, where a 225 MHz beam caused an increase in the animal´s body temperature. Depending on the dosage level, the temperature increase occurred within a time of 15 to 30 minutes. After the beam was removed, the animal´s body temperature decreased back to normal. The report suggests the technique could be useful for controlling crowds or in negotiations.

While the investigations reveal intriguing techniques for non-lethal torture, the report does not mention plans for carrying out specific experiments or studies in the future.

http://physorg.com/news122567894.html

[vigilant]

When exposed to pulsed RF energy, humans experience the immediate sensation of "microwave hearing" - sounds that may include buzzing, ticking, hissing, or knocking that originate within the head.

Studies with guinea pigs and cats suggest that the mechanism responsible for the phenomenon is thermoelastic expansion.


thermo (heat) elastic (pliable) expansion

Sounds like severe temporary Tinnitus, caused by heating of the inner ear to me....

[elfismiles]

Thanks for more data AmericanDream.

Here is a link to my own article on this decades old technology:

ANOMALY Magazine: Guided By Voices
by SMiles Lewis / February 1, 2008
http://www.anomalymagazine.com/2008/02/ ... by-voices/

[Wilbur Whatley]

elfismiles, Extremely interesting article! Makes me think back to Julian Jaynes' very strange book called The Origin of Consciousness in the Breakdown of the Bicameral Mind (1976).

Just tonight I was talking with my genius IT guy, who was putting in a new server for me. I was telling him how recently I've been having these spells where I feel like suddenly I'm in the middle of a high-energy pulse, which I barely perceive as a very high-pitched whining and some uncomfortable anxieties, and then it fades in a few seconds. Probably doesn't last for more than 5 or 10 seconds at a time, but very alarming when it happens. Maybe it's some kind of neurological problem, but I think it is some kind of cell tower or microwave burst. We live in a sea of radiation.

Of course, maybe I have an alien implant in my brain. This is Philip K. Dick territory.

I'm not surprised at all to hear that focused energy beams could cause people to hear voices.

[elfismiles]

elfismiles, Extremely interesting article! Makes me think back to Julian Jaynes' very strange book called The Origin of Consciousness in the Breakdown of the Bicameral Mind (1976).

Just tonight I was talking with my genius IT guy, who was putting in a new server for me. I was telling him how recently I've been having these spells where I feel like suddenly I'm in the middle of a high-energy pulse, which I barely perceive as a very high-pitched whining and some uncomfortable anxieties, and then it fades in a few seconds. Probably doesn't last for more than 5 or 10 seconds at a time, but very alarming when it happens. Maybe it's some kind of neurological problem, but I think it is some kind of cell tower or microwave burst. We live in a sea of radiation.

Of course, maybe I have an alien implant in my brain. This is Philip K. Dick territory.

I'm not surprised at all to hear that focused energy beams could cause people to hear voices.

Hi WW,

Thanks for the comment on my article.

Do you have wifi in your house or work areas? EMF is a health hazard even for people who aren't extraordinarily sensitive, aka electro-hypersensitive. Even just having a regular alarm-clock/radio next to the head of your bed can be potentially bad.

Check out my good friend Jim Beal's website (that I host) who is an expert in those areas:

www.EMFinterface.com

Minimizing exposure is the key.

- SMiles

[starviego]

Related info here:

http://rigorousintuition.ca/board/viewt ... ght=kinkel

[Wilbur Whatley]

elfismiles and starviego, thanks for very interesting responses.

I've bookmarked them, and will read them all.

elfismiles, I have wifi in the house/office where I was working tonight and experienced that emburst, but I have also been experiencing them, maybe every two or three days or so, never more than once or twice a day, in my residence house, which is four miles away in the countryside and has no wifi.

I'm only 15 or 20 miles from the presidential compound at Camp David. I've wondered whether this is some kind of emergency communications frequency that gets blasted through my body.

By the way, unlike some others in my extended family, I have no history whatsoever of psychosis or hearing voices, etc. I drink too much, but I'm not crazy.

[hmm]

February 18, 2008

Pentagon Report Investigated Lasers that put Voices in your Head
by Lisa Zyga

While the investigations reveal intriguing techniques for non-lethal torture, the report does not mention plans for carrying out specific experiments or studies in the future.

http://physorg.com/news122567894.html

something similar in this old thread:

http://rigorousintuition.ca/board/viewtopic.php?t=1270

transcranial magnetic stimulation,including a wired magazine article from 1999 called "this is your brain on god" about a researcher that tested it on religious people who thought god was talking to them in their heads...

[brainpanhandler]

This is the sort of technology I was contemplating on the Woodward claims new Manhattan Project won Iraq war thread.

http://rigorousintuition.ca/board/viewt ... 76&start=0

Imagine how this technology could be used in an interrogation. Or imagine that you could direct this technology at suspected terrorists/enemy combatants/insurgents. For instance, you could, with the voice of Allah, instruct a suspected terrorist to perform various actions, like gathering materials for a bomb. If the suspected terrorist complied with the instructions then you've identified an insurgent.

[brainpanhandler]

I've been having these spells where I feel like suddenly I'm in the middle of a high-energy pulse, which I barely perceive as a very high-pitched whining and some uncomfortable anxieties, and then it fades in a few seconds. Probably doesn't last for more than 5 or 10 seconds at a time, but very alarming when it happens.

Is this experience also accompanied by a sense of increased pressure in your skull? Are there any visual anomolies associated with these episodes? Dizziness? Headaches? Heart palpatations? Tingling skin sensations?

You should start keeping a journal and record as many details of these episodes as possible including as much detail about the context as possible. You might begin to see a pattern. I would be curious to hear any further details so I can compare with my own experiences.

I have recently been rereading Orgone, Reich and Eros by W. Edward Mann and rediscovering what subtle, delicately energetic creatures we are.

[Pierre d'Achoppement]

Or imagine that you could direct this technology at suspected terrorists/enemy combatants/insurgents. For instance, you could, with the voice of Allah, instruct a suspected terrorist to perform various actions, like gathering materials for a bomb.

"I always have the martyrdom tape. I always listen to it. (...) These are very special tapes. They indicate the direction to the martyr. These will facilitate everything when you listen to them. They enter your body, but you must listen to them constantly."

source

[Penguin]

Wilbur Whatley :
Northern Lights can also cause people to hear crackling, hissing sounds...
A friend of mine worked for a while in a research lab that investigated aurora borealis, and he personally heard these sounds. He said it felt like it was coming from inside his head, not thru the ears. The lab has been trying to prove that the sounds exist (most of the researchers have heard them) by using very sensitive mics. The time he heard it, the mics didnt capture anything - which points to it being an electromagnetic phenomenon that the brains perceive as sound.

[brainpanhandler]

Wilbur Whatley :
Northern Lights can also cause people to hear crackling, hissing sounds...
A friend of mine worked for a while in a research lab that investigated aurora borealis, and he personally heard these sounds. He said it felt like it was coming from inside his head, not thru the ears. The lab has been trying to prove that the sounds exist (most of the researchers have heard them) by using very sensitive mics. The time he heard it, the mics didnt capture anything - which points to it being an electromagnetic phenomenon that the brains perceive as sound.

Fascinating. I had never heard of that. I live far enough north that we occasionally get to view the northern lights. I imagine living in Finland you see them quite often.

If it is true that EM energy associated with the aurora borealis are audible then I would imagine that indigenous cultures in the northern latitudes have stories about them.

[brainpanhandler]

The following is an excerpt from the introduction to a Master's thesis by Janne Hautsalo

HELSINKI UNIVERSITY OF TECHNOLOGY
Department of Electrical and Communications Engineering
Laboratory of Acoustics and Audio Signal Processing

1.1 Historical Perspective and Previous Studies
Northern lights have been a source of myths and folklore that originate from ancient times.
Actually, the Finnish word for the aurora, revontuli (i.e. fox fire), has its origin in a myth
which explains that northern lights are given birth by a fire fox striking fire with its tail.
Aurorae have usually been associated with the supernatural and they have awakened
strong emotions, even fear, among people. Often the aurorae have been considered as a bad
omen, predicting war, disaster or plague.
Inhabitants of the west coast of Norway used to believe that the northern lights were “old
maids” dancing and waving white gloved hands. Connections between the aurora and old
women were common in Finland, too, where it was believed that the northern lights were
“old women of the North hovering in the air”. [13]
Among the Inuit in Greenland and the Hudson Bay area, the northern lights were the
realm of the dead. The Greenlander Inuit believed that a flickering northern light signi-
fied that their dead friends were trying to contact surviving relatives. The Greenlanders
respected the northern lights deeply and therefore avoided making fun of them. The same
kind of connections between aurora and unborn and departed souls are found in ancient
China and some Siberian tribes. Another widespread belief among the Inuit tribes was that
the aurorae were spirits playing football with a walrus skull. [13, 20, 22]
There exist attempts to explain aurora with more scientific basis, such as the interpretations
that the aurorae were reflections from far-off locations. E.g. in Norway it was believed
that the aurorae were reflections of shoals of silver herring in distant oceans, or icebergs in
the North Atlantic. Some Sámi people believed that the aurorae were simply “thunderstorms”
of the winter [20]. This is interesting, for this characterization could also refer to
the presence of an elecric type of sound.
The aurora seems to have inspired many of the wise men of history. Even Aristotle
(384–322 BC) most likely witnessed some auroral displays, although they are very rare in
Mediterranean countries. Aristotle’s science had four elements: fire, air, water, and earth.
He described in his Meterologica how a vapor caused by the sun rises from the earth and
collides with the element fire, which then bursts into flames producing an aurora. [20, 22]
In older times it was a fairly world-wide belief that the aurora was some kind of fire. Our
ancestors in Nordic countries believed that the northern lights were active volcanoes in the
far north placed there by the God to light up and heat the dark and cold parts of the country.
CHAPTER 1. INTRODUCTION 4
Even the world-famous scientist Anders Celsius noted in his diary on September 24th, 1732
that the aurora was caused by active volcanoes close to the North Pole. [13]
Though the present scientific knowledge of the aurora is able to explain the phenomenon,
some myths still live among the residents of the Arctic. One of these myths is that one can
communicate with the aurora by whistling. It is believed that by whistling to the aurora,
one could accelerate its motion. The Greenlander Inuit believed that one could even receive
a rustling sound from an aurora, meaning that contact had been established with their dead
friends. This brings the aspect of aurora related sound to the picture. In the survey of aurora
related sound observations arranged by SGO (further discussed in Chapter 7) eight people
reported that whistling had affected the aurora [37]. Though the real scientific validity
of observations like this may not be high, the folklore and myths of the aurora form an
interesting foundation of material for the study of cultures and people throughout history.
1.1.1 Aurora Related Sounds in Literature and Arts
International literature provides many potential references to aurora related sounds. It has
been suggested that the earliest reference to aurora related sound is found in Germania,
written by the Roman historian Tacitus (55-117 AD):
Beyond them is another sea, calm even to stagnation by which the circle of the
earth is believed to be surrounded and confined; because the last gleam of the
setting sun lingers till he rises again, and so brightly that it dims the stars. It is
believed too that a sound is heard, that the forms of gods and rays from a head
are seen. [13]
Eather [20] says that a number of references in Norwegian sagas to the song of the
Valkyries could be interpreted as referring to auroral sounds. The aurora was explained
as a flickering light from their armor as they rode through the skies.
Perhaps the best known assumed biblical description of aurora is found in The Old Testament’s
Book of Ezekiel (1:22-24), which also has a potential reference to aurora related
sounds. The sound is compared to the “noise of great waters”:
22. And the likeness of the firmament upon the heads of the living creature was
as the colour of the terrible crystal, stretched forth over their heads above. 23.
And under the firmament were their wings straight, the one toward the other:
every one had two, which covered on this side, and every one had two, which
covered on that side, their bodies. 24. And when they went, I heard the noise
of their wings, like the noise of great waters, as the voice of the Almighty, the
voice of speech, as the noise of an host: when they stood, they let down their
wings. [11]
CHAPTER 1. INTRODUCTION 5
A number of poets have expressed the sounds of aurora. The British poet William
Wordsworth (1770–1850) describes the aurora and its sound in his poem The Complaint
of a Forsaken Indian Woman, composed in 1798:
In sleep I heard the northern gleams;
The stars, they were among my dreams;
In rustling conflict through the skies,
I heard, I saw the flashes drive,
And yet they are upon my eyes,
And yet I am alive;
Before I see another day,
Oh let my body die away! [62]

link: Last result on this page

[Penguin]

Ill post some resources, translate a couple synopsis from finnish, and try to find some english ones too..

My friend worked up north, in Sodankylä observatory.

Ive been up in Lapland a few times - where auroras are the most common. They do appear further south occasionally, but mostly only during winter, and when the weather is very cold and clear. Ive seen them in the south a few times too - once they were bloody magnificent, with the whole starry sky gleaming red, blue and green. It was awesome...I was simply standing outside, in -25 C, thickly dressed, stretching my neck till it hurt The cold weather isnt a requirement for auroras, its simply because when its winter, cold and starry, you can easily see them

Once in Lapland I woke up in a tent, to go out to pee - thinking it was already morning. Wrong I was - going out the tent I see the whole sky shimmer a bright green, with brighter ridges moving about. I havent witnessed the sounds myself, but that friend of mine is one of those persons youd trust your life with. Hes also a musician, so I trust he knows when his ears are sending signals, and when its his brain perceiving something else.

Yup, myths and legens about auroras are very prevalent, in both the Saami people up Lapland (theyre not the same as Finns - Saami people are the first settlers here after the Ice age 10 000 years ago. Saami people are nomadic reindeer herders, up till today - today they just use Skidoos instead of reindeers to pull their sleds when they are working the herds.), and among us Finns - Kalevala, the mythic epic as well.

http://www.fmi.fi/tutkimus_avaruus/avaruus_67.html
The Finnish Meteorogical Institute - "Systematic aurora research has been ongoin ever since 1700s, in the Academy of Turku. At that time, the sightings were simple - mark down the dates and times of the auroras. This data is available for over a hundred years, enabling study of temporal changes in the phenomenon. There are similar data series from other European universities as well. In Helsinki, a study G.G. Hällström (1775-1844) "De Apparitionibus Aurorae Borealis in Septentrionalibus Europae Partibus" year 1847, contained about a 1000 sightings."

Nowadays the research has been in far north, since early 70s. They have several sky cameras operating on many freququency spectrums, shooting the sky continuosly all year round, in addition to radars and audio microphones (im not sure if the audio project is continuous). There is a collected data pile of 100 000 hours of observations, 34 000 of which are Aurora lit.

http://www.ava.fmi.fi/MAGN/PICS/nakyvyysajat.gif
The time distribution of visible auroras...Theyre so common that you dont need to spend many nights in the woods to witness them. A weeks trip - youre almost guaranteed to see them - on wintertime that is, during summer the sun doesnt set at all...Making visibility poor.

FMIs official explanation for the sounds atm:
"
Revontulien väitetty rätinä tai muut äänet ovat hyvin yleisiä uskomuksia kaikkialla, missä revontulia nähdään. Taivaan ollessa mahtavasti loimuavien revontuliliekkien peitossa, saattaa helposti syntyä mielikuva nuotiotuliin tai tulenlieskoihin yleensäkin, joihin liittyy erottamattomasti tulen rätinä. Ehkä ihminen mielikuvituksessaan lisää puuttuvan äänisignaalin revontulien palaessa taivaalla, ja jälkeenpäin kuviteltu ääni tuntuukin jo todelliselta. Ilman tiheys revontulien esiintymiskorkeudella on niin tavattoman pieni, ettei ihmiskorvan kuultavia ääniä sieltä voi välittyä. Kirkkaat revontulivalot ja niiden nopeat liikkeet saattavat silmä-ärsytyksen kautta käynnistää tiettyä kuuloa aktivoivia fysiologisia reaktioita, jotka saattavat aiheuttaa kuuloelimiin tinnitystä, vinkunaa."

Which says - the claimed sounds would be caused by visually thinking of fireplaces crackling when seeing auroras, or the eyes being stimulated by the sights, causing tinnitus. Damn laughable idea imho, when its known that EM energy can affect the brain directly, and that the brain function normally synchronized to Earths magnetic fields resonance (the Schumann resonance). http://en.wikipedia.org/wiki/Schumann_resonance

http://aurora.fmi.fi/public_service/index.html
Here you can see aurora predictions, and data about the magnetic field activity.

http://aurora.fmi.fi/public_service/ima ... link_1.gif
Latest image from the Sodankylä camera

http://www.geo.mtu.edu/weather/aurora/index.html
English page from MTU

The earliest written reports of auroral sounds are from the 1500s...
There is no scientific consensus on the issue - mostly due to the fact that most scientists are so dense that if they cant record the sounds with an audio mic, they think they cant study them...If people hear them, mics not, then it would be pretty reasonable to start studying the brain/EM angle, instead of flogging the sound wave issue
http://www.acoustics.hut.fi/projects/au ... ounds.html Only in finnish, this one, but explains the EM theory quite well. I believe he is one of the guys who has worked in Sodankylä, on that audio project.

http://members.tripod.com/auroralsounds/ This one in english:
"The northern lights attract millions of people. Ever since aurora has been seen there have been people able to hear their sounds. It is not known where the sounds come from.

There is no accepted theory which can approve and explain or disprove crackling, rustling, and swishing sounds that are sometimes heard in connection with aurora. There are even doubts about the existance of these sounds. Here we describe the auroral sounds and introduce some of the most popular theories that explain them.

Most probably we will not know the right answer so soon. Scientists of northern lights are just too busy with the ionosphere where the lights originate, the Earth mangetosphere where the charged particles that create aurora are accelerated, and the solar wind that drives the whole thing."

"Character of the sounds

There are no tape recordings available so we should try to imagine the sounds from descriptions of eyewitnesses. Here aer some witness reports

- It could compare to the sound of a radio left on a station that has gone off the air
- a faint crackling or light rustle
- A definite hissing sound
- Like balled cigarette pack cellophane crinkled next to ear.
- crackling, rustling sound
- a small animal scampering in grass or leaves
- someone standing a good distance away ... with a LARGE, very flexible sheet of metal ... flexing [it] back and forth ... Low. Slow. wubble/wrang/wubble/wub ... a secret sound
- sizzling, popping, swishing, snapping, whooshing
- low "hissing"
- soft crackles, tiny pops, and almost static electricity like sounds
- Electric silk. Soft, rippling, crackly
Conditions necessary to hear auroral sounds

It is not clear which conditions should be satisfied for the auroral sounds to be heard. However, most of the observations indicate that sounds are heard during periods lasting a few minutes or more during which a powerful display of the aurora can be seen right above the head.

To imagine how skies may look like when auroral sounds are heard you can watch a movie composed of pictures taken by the all-sky camera in Poker-Flat, Alaska. The picture includes the view of all skies, where the North is downwards, the South is upwards, and the skies above the head are in the middle of the picture. The pictures are black and white, in reality white would correspond to a greenish color of aurora. From movie you can see that the time of the most powerful aurora display longs for just about 20 minutes.


It also seems that not everybody can hear sounds. There are many people that have seen hundreds of powerful aurora displays without any signs of sounds. At the same time, there are observations where in a group of people everybody have heard the sounds (in observation list almost half of all cases). Common to all observations is the fact that sounds have been heard only once or twice in a life time. The observations indicate that the auroral sounds are real but can be heard on very rare occasions.
Most popular theories

There are not many studies of the auroral sounds in the scientific literature. There are not many attempts to register auroral sounds either. One of the explainations is the large scepticism about the subject which dominates among the space scientists.

The most thourough studies of auroral sounds has been done by Silverman and Tuan. They have presented a large list of observations, they have done statistical, geographical and other type of analysis on these data, and they have pointed out possible theories that may explain at least parts of auroral sound observations. Silverman and Tuan favor the brush discharge theory even though they are not certain about it. Another large contribution has been done by Colin Keay. He favors the theory that electromagnetic waves are transduced into acoustic waves. He even points out that sounds from meteorites have similar character as the auroral sounds. Below are most popular theories that explain the auroral sounds
It's ringing in you ears. Tinnitus.

This theory is appreciated by those who have seen a lot of aurora but have heard nothing. Tinnitus is the noise in the ears which you can hear anytime, just find some silent place. Tinnitus explains why many 'reliable' persons do not hear auroral sounds - they simply can differ the ringing in the ears from the 'real thing'. The difficulty of this theory is that the character of tinnitus sounds differs from that of auroral sounds. In addition, tinnitus theory does not explain why similar sounds are not observed in connection with other nature phenomena.
Electromagnetic waves transduced into acoustic.

This theory was proposed by Keay in 1980. It shows that audio-frequency electromagnetic waves can partially transfer their energy into acoustic waves with the help of appropriate objects in the vicinity of the observer. These objects can be hair, grass, trees etc. The laboratory experiments show that the 'most sensitive' subjects could perceive electric field peak-to-peak variations as low as 160 V/m for waves with frequency 4 and 8 kHz. However, the sensitivity among subjects could vary thousand times.

Electromagnetic waves with audio frequencies are observed during the aurora both in the space with satellites and on the ground with radio antenna. Strong waves are observed also in connection with fireballs (very strong meteors falling on the earth) and nuclear explosions. In both cases sounds have the same character as auroral sounds.
Direct transmission of audible sound

The auroral lights originate at heights from 60 to 400 km. One may assume that sounds are produced inside the aurora and afterwards propagate down to the earth. Then the sound will attenuate because of the spreading. In addition, the attenuation of high frequency sounds makes that there will be only 0.1% of 40 Hz wave energy reaching the ground level from the height 60 km, and even less for higher frequency waves. As a result, high frequency sounds will not be audible. Only ion acoustic waves with frequency around 1 Hz and less (infra sound) can propagate practically unattenuated. The infra sounds have been registered by scientific instruments, however, they are too weak to be audible.

There is an additional problem with the theory of direct sound transmission. It takes a few minutes for the sound to propagate from the aurora altitude down to the ground. However, most of the observations report the simultaneous aurora movement and sound appearance.
Brush discharge

This theory is favored by Silverman and Tuan. Brush discharge occurs from point-like electrodes where sharp potential gradients exist. It can be trees, bushes, hair and other sharp protruding objects. The discharge can produce sounds from rustling up to hissing. The necessary electrical field to trigger the brush discharge is around 1500 V/m. Remember that the electrical field of the order 100 V/m in the open air is present permanently. During the periods of the strong aurora the electrical field can reach values of 1000 V/m and more. However, the changes in the electric field are not instaneous but with the rise time of the order ten seconds. Again, it is difficult to explain observations of instantenous changes in the sound which follow the development of the aurora.

The brush discharge can have some side effects like tingling of the skin, or smell of the ozone (produced during the discharge). There are a few observations that indicate the smell of the ozone."