Fizician roman face avioanele Mig-21 invizibile

Aldulescu, on 19 mai 2019 - 17:19, said:

Da, cam asa se face, doar ca este vorba despre ioni si plasma si este un concept utilizat deja la prototipuri. In varful avionului este un generator de plasma, iar plasma usureaza inaintarea avionului la viteze supersonice, dar in acelasi timp micsoreaza ori deformeaza semnatura avionului pe radar.


Plasma surrounding an aircraft might be able to absorb incoming radiation, and therefore reduces signal reflection from the metal parts of the aircraft: the aircraft would then be effectively invisible to radar at long range due to weak signals received.[9] A plasma might also be used to modify the reflected waves to confuse the opponent's radar system: for example, frequency-shifting the reflected radiation would frustrate Doppler filtering and might make the reflected radiation more difficult to distinguish from noise.



http://www.spacedail...future-00o.html

Some researchers suggested that since ionised gases absorb radio signals, a plasma envelope would make missiles and aircraft practically invisible to radar.

Plasmas can interact strongly with electromagnetic radiation: this is why plasmas might plausibly be used to modify an object's radar signature. Interaction between plasma and electromagnetic radiation is strongly dependent on the physical properties and parameters of the plasma, most notably the electron temperature and plasma density.
The use of plasmas to control the reflected electromagnetic radiation from an object (Plasma stealth) is feasible at suitable frequency where the conductivity of the plasma allows it to interact strongly with the incoming radio wave, and the wave can either be absorbed and converted into thermal energy, or reflected, or transmitted depending on the relationship between the radio wave frequency and the characteristic plasma frequency. If the frequency of the radio wave is lower than the plasma frequency, it is reflected. if it is higher, it is transmitted. If these two are equal, then resonance occurs. There is also another mechanism where reflection can be reduced. If the electromagnetic wave passes through the plasma, and is reflected by the metal, and the reflected wave and incoming wave are roughly equal in power, then they may form two phasors. When these two phasors are of opposite phase they can cancel each other out. In order to obtain substantial attenuation of radar signal, the plasma slab needs adequate thickness and density.[9]

Plasmas support a wide range of waves, but for unmagnetised plasmas, the most relevant are the Langmuir waves, corresponding to a dynamic compression of the electrons. For magnetised plasmas, many different wave modes can be excited which might interact with radiation at radar frequencies.

https://en.m.wikiped.../Plasma_stealth

Edited by Infinitty, 21 May 2019 - 09:22.

Un avion înconjurat de plasmă este o pisică cu clopoței, pe lângă că este văzut foarte bine pe radar se va vedea foarte bine și pe infraroșu iar marea majoritate a rachetelor antiaeriene au ghidare pe infraroșu.

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Gata, s-au făcut invizibile. De astăzi nu mai zboară niciunul, au fost retrase din uz.