Stealth plasma could challenge 75 years of air defense strategy



In our October 19, 2021 article on the Russian hypersonic missile Zircon, we quoted Kremlin Deputy Prime Minister Yury Borisov, who said: “We have made progress, in particular, in the area of ​​hypersonic weapons and (those) based on new physical principles.

Now it turns out that these “new physical principles” may not be that new after all, but rather date back to 1999 and have to do with plasma stealth. Plasma stealth is the use of ionized gas, or plasma, to reduce the radar cut (RCS) of an object, such as an aircraft.

As we have described, hypersonic vehicles or weapons fly so fast that the air in front of them forms a plasma cloud which absorbs or interferes with radar waves, making the object virtually invisible to radar systems.

What is plasma?

Plasma is often referred to as the fourth ground state of matter, along with solid, liquid, and gas. Plasma is a material in which one or more orbital electrons are torn from atoms, forming an ionized gas.

Plasma is the most abundant regular form of matter in our universe, and by “regular” we do not mean dark matter or dark energy. Plasma is what makes up the stars, including our Sun, and two examples of plasmas used in our daily lives are neon signs and plasma televisions.

Plasma can be created by heating an inert gas or by subjecting a gas to a strong electromagnetic field. The presence of free particles in a plasma makes it electrically conductive and sensitive to electromagnetic fields applied from the outside.

A-12 reconnaissance aircraft. Source: USAF / Wikimedia Commons

Plasma has been shown to interfere with radar waves, reducing the radar cross section (RCS) of an aircraft. Known as plasma stealth, the technology to take advantage of it was first proposed in 1956 by a General Electric engineer named Arnold Eldredge. During the 1960s, the Central Intelligence Agency (CIA) of the United States funded a project to reduce the RCS of American reconnaissance planes, in particular the Lockheed A-12, which used a fuel additive containing cesium to significantly reduce the radar signature of its engine, and an electron beam to generate an ionization cloud in front of the air inlets to help conceal its entire rear aspect from radar waves. The system has been tested but has never been deployed in an operational manner.

What is a radar?

Long range radar
A long-range radar used to track space objects and ballistic missiles. Source: Wikimedia Commons

Radar, which means Radio Ddetection asd Ranging, is a detection system that consists of a transmitter that produces electromagnetic waves in the radio or microwave spectrum, a transmitting antenna, a receiving antenna, a receiver and a processor. Radio waves, which can be pulsed or continuous, reflect off an object and then return to the receiver, and the round trip time, strength, and Doppler shift of the reflected signal provide information about range, size, and speed .

How radar works
How does radar work. Source: Smithsonian Institution

The first radar units were developed in secrecy by several nations just before and during World War II. A key development was the invention of the cavity magnetron in the UK, which enabled the creation of relatively small systems with sub-meter resolution. A cavity magnetron is a high-powered vacuum tube capable of generating microwaves by using the interaction of a flow of electrons with a magnetic field while passing a series of small open cavities.

Radar is used to detect planes, ships at sea, spacecraft, missiles, weather formations, terrain, and even cars on the roads. If you’ve ever passed a policeman stopped by the side of a road by pointing a radar gun at oncoming traffic, you’ve already seen the radar in use. Aircraft are equipped with a radar system called TCAS, which stands for Ttraffic alert and VScollision Acancelation Ssystem, to help them avoid mid-air collisions. However, there is a flaw in the ability of all radars to detect objects, and that is plasma.

Defeat the radar

The National Aviation Reporting Center on Anomalous Phenomena (NARCAP), reported an incident that occurred on the evening of March 19, 2020, when two FedEx pilots were flying a Boeing 767 cargo plane 37,000 feet northbound over Monterrey, in Mexico. Suddenly, a bright object fell from the sky above them, then followed their pace for over 30 minutes, hovering between 1,000 and 2,000 feet (305 – 610 m) above the tip of their wing.

Grabbing a video camera, the captain recorded the encounter, which showed a shiny object enveloped in a shimmering, pulsating cloud of plasma. What the captain did next was the most interesting thing, he tilted the video camera to show his radar screen which, although the object was clearly visible through the aircraft’s windshield, only showed no sign of the object on the radar.

Aircraft TCAS screen
Aircraft TCAS screen. Source: Jemr69 / Wikimedia Commons

NARCAP Director Ted Roe said The daily mail that the meeting “… confirmed what I said from the beginning, that is to say that the UAP [Unidentified Aerial Phenomenon] are detected intermittently on the radar. He turned his camera over to his radar screen and there was no detection. ”

In January 1999, the Russian news agency ITAR-TASS published an interview with Anatoly Koroteyev, who was the director of the Russian Scientific Research Institute for Thermal Processes, now called the Keldysh Research Center. In the interview, Koroteyev described a stealth plasma device developed by his organization.

In its June 2002 issue, the Electronic Defense Journal reported that “plasma cloud generation technology for stealth applications” developed in Russia reduced an aircraft’s RCS by a factor of 100 and was tested on a Sukhoi Su-27IB fighter-bomber.

Now known as The Journal of Electromagnetic Domination, this journal is published monthly and covers developments in electronic warfare, signals intelligence, electronic intelligence and communications intelligence. It is published by the Association of Old Crows, headquartered in Alexandria, Virginia, and is an international, non-profit professional organization specializing in electronic warfare and tactical information operations.

The name “Old Crows” comes from the use of electronic warfare to disrupt Axis communications and radars during World War II. The Allied Equipment Operators were known as “Crows”, which over time became “Crows” and then “Old Crows”.

Using Stealth Plasma

When an electromagnetic wave encounters a plasma, the wave transmits energy to the ions and electrons in the plasma. Some of the energy from this wave will be returned to the wave by the particles, and some will become heat. If a plasma absorbed all of the energy from an incoming radar wave, it would reduce an object’s RCS to almost undetectable levels and make that object almost entirely invisible to radar.

Difficulties arise because radar waves have very variable frequencies. Many ffighter planes are equipped with attack and reconnaissance radars operating in the 8.5-11 GHz and 13-18 GHz bands; the short wavelengths of the 2.7-10.5 GHz band are widely used for surface search, low-flying target detection and ship piloting; while radars above the horizon can operate in the HF band (3-30 MHz) and space surveillance and early warning radars operate in the VHF and UHF bands.

Due to the varying frequencies of the radar waves used, a plasma must be variable in terms of density, temperature and magnetic field.

Another difficulty is the amount of electricity required to produce a plasma large enough to surround an entire aircraft. A more economical solution is to surround only the most reflective surfaces on an aircraft, such as its turbojet fan blades, engine air intakes, vertical stabilizers, and the aircraft’s own radar antenna.

Starting in 2010, aircraft manufacturer Boeing filed a number of patents relating to plasma stealth. These include a system for controlling air flow with electrical pulses, a plasma generating device used to create a plasma flow on the trailing edge of an aircraft that can change its RCS, a plasma actuator system used to camouflage an open weapon bay on a fighter, a cascade array plasma actuator for use on a rotor blade, and a system for controlling airflow over the surface of the hunter wing with pulsed discharge.

Whether plasma stealth is the “new physics” the Russians described or not, the point is that the systems we have relied on for more than half a century to keep our skies safe are going to have to change and evolve.



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