Earth’s Ionosphere

About the Ionosphere

What is the ionosphere?

How is the ionosphere formed?

The importance of the ionosphere to radio communications

The importance of ionospheric research

Active ionospheric research and the HAARP project

What is the Ionosphere?

Atmospheric Layers Troposphere The temperature decreases with altitude.The end of troposphere at 10-15 km called the tropopause StratosphereExtends to 50 km. The temperature increases with altitude while

the pressure is dropping. Ozone is the most critical stratospheric ingredient from the human point of view.

MesosphereExtends from 50 to 80 km. The temperature steadily declines.

Little known about it, often called the ignorosphere.

ThermosphereExtends from 80 to 300 km, is characterized by increasing temperature from 500C to 2,000C. The air composition starts to deviate from the one at sea level.

Exosphere Extends from 300 km to the region where the atmosphere merges with interplanetary gases. The gas density is low, composed of He and H.

Ionosphere Extends from 50 km to about 1,000 km. In this region ions and electrons coexist. Is divided into subregions, called D, E and F regions corresponding to different densities.

Above 1,000 km the ionosphere merges into the heliosphere where helium is found. Above a few thousand km it merges into protonosphere, where p is dominant. At the higher altitudes it merges with the interplanetary gas.

The ionosphere is an example of a plasma. Plasma is neither gas, liquid nor solid; it is the fourth state of the matter and comprises of 99% of visible matter in the Universe.

How is the Ionosphere Formed?

•Solar radiation strikes the atmosphere with a power density of 1,370 W/sq. meter. This radiation is spread over a broad spectrum ranging from RF through IR and visible light to X-rays. •Solar radiation at UV and shorter wavelength is “ionizing” radiation. Photons of high energy are capable of dislodging an electron from a neutral atom.

How the ionosphere get its structure?

•At the highest level of the Atmosphere solar radiation is strong but there are few atoms to interact with, so ionization is weak.

•As the altitude decreases more gas atoms are present so the ionization process increases.

•At still lower altitudes, the gas density increases further and there is moreopportunity for the photon absorption. However the intensity of solar radiation is smaller at these altitudes, since some of it was absorbed at the higher level.

•The ionization peaks at the point where lower radiation and greater gas densityare balanced out. Thus the ionization layers are formed

The importance of the ionosphere to radio communications

In 1864 James Clerk Maxwell published a theory of electromagnetic waves.

In 1899 Guglielmo Marconi converted this theory into the first practical telegraph system sending signals across the English Channel.

In 1901 he demonstrated transatlantic communication. He was awarded the Noble Prize in Physics in 1909.

Marconi’s experiment raised a serious scientific dilemma. It was believed that E.M. waves traveled in straight lines. So how can they reach a distant receiver?

In 1902 Oliver Heaviside and Arthur Kennely came out with the explanation

Implications to the wireless communications

For the most of the 20 century wireless communications relied on HF frequencies (3-30 MHz)

The applications include:•Radio Broadcasting (WOA uses a few hundred MW transmitters)•Jamming (in the former SU 80% of operational capacity of HF-transmitters were used for jamming)•Military communications and surveillance•Ship-to-shore communications•Trans-oceanic aircraft links

All based on the ionospheric reflection

Ground-to-Satellite Communications such as GPS

Use UHF frequency (300 MHz - 3 GHz)

When propagating through the ionosphere such signals experience Refraction and scattering by ionospheric irregularities which have a major impact on system performance and reliability.

The sun has a dominant effect on the ionosphere, solar events such as flares or CME’s can lead to worldwide communication “blackouts” on the short wave bands.

Thus the ionospheric research which can model and predict the ionospheric conditions is of great practical importance.

How the magnetic field shields the earth

Active Ionospheric Research

You can ether observe natural fluctuations of radio signals caused by ionospheric variations, or study artificial perturbations of the ionosphere.

The latter can be done by using powerful radio transmitters to heat up the ionospheric plasma.

The first time the HF heating effects were discovered in 1933. It was called Luxembourg effect or cross-modulation.

Basic PhysicsBasic Physics: a : a powerful radio wave powerful radio wave heats the ionospheric heats the ionospheric electrons thus electrons thus modulates their modulates their temperature. It effects temperature. It effects the absorption rate of the absorption rate of the probe wave. The the probe wave. The latter picks up latter picks up modulation of the modulation of the powerful heating wave.powerful heating wave.

Theoretical Developments Related to HF-Heating

Bailey [1938] suggested that electron gyro-heating of E-region could sustain a glow discharge.

In 1961 he suggested that an artificial mirror can be created in the E-region.

Active Ionospheric Research

A number of powerful facilities was developed since to study artificial modifications of the ionosphere.

The most advanced facility for such studies is called HAARP (The HF Active Auroral Research Program). It is located in Alaska.

The HAARP FacilityIs located near Gakona, Alaska. 3 MW

transmitter and antenna system radiate waves in the range 3-10 MHz.

Includes a number of diagnostic instruments.

HAARP was designed based on ideas by Nikola Tesla (1856-1942)

Dr. Nikola Tesla was a poet/scientist, magician/engineer, visionary/pragmatist,pacifist/weapon designer. He was born in Serbia, graduated from Prague University,arrived in NY in 1884.

He first went to work with Thomas Edison but a disputegrew between the two. Edison favored direct current whileTesla believed in the more economic alternating current. This rift sent Tesla to Edison’s rival, George Westinghouse.

Tesla experimented with lightning, power generators andElectrical transmission systems. Wireless radio was Tesla’s concept, as well as radar and florescent lighting.He patented the electromagnetic weapons with the desire not to destroy, but to serve humanity by maintaining order.

Why HAARP is located at high latitude?

The high latitude ionosphere is a very special region in the Earth system.

The most distinct characteristic of the high latitudes (above 60 deg.) is the aurora borealis.

The observed emissions are due to neutrals that have been ionized and excited by the energetic particles and are subsequently returning to their ground state by emitting radiation.

The presence of strong currents and therefore electric fields is a key characteristic of the high latitude ionosphere.

These currents are caused by the interaction of Solar wind with the magnetic field at altitudes of several thousand of kilometers..

The magnitude of the currents, known as auroral electrojets, flowing in the D and E regions is of the order of 10^6 Amperes and carry an energy of about 100 GW.

What is HAARP used for?• Generates extremely low frequency waves for communications with submarines

• Conducts geophysical probes to identify and characterized natural ionospheric process so that techniques can be developed to mitigate or control them.

Underground Imaging

Radiation Belt Control

Planetary and Solar HF-radar

ELF Generation by the pulsed HF-heating of the Ionosphere

Some Physics Aspects Skin depth is that

distance below the surface of a conductor where the wave intensity drops e-times

In a seawater SD is about 100 m for f=0.1kHz

Communication with Submerged Submarines

Tunnel Detection/Underground Exploration

Tunnel image resulting from inverting the apparent resistivity data with remote reference processing.

Radiation Belt Control

Schematic illustration of precipitation of radiation belts particles induced by injection of low-frequency waves

Voices of HAARP’s opponents

They Called it Vandalism in the Sky, but why?

“The system had been developed for manipulating and disrupting human mental processes through pulsed radio frequency radiation over large geographical areas”.

(reference to Zbignev Brzeniski?) “Weather modification by altering upper

atmosphere wind pattern”. “Ozone distruction” (ref. to Dr. Elizabeth

Rauscher, an expert in high-energy physics).