Plasma Stealth

[AlfaSigma]

I'm surprised that there isn't more talk about plasma stealth. Based on what I've read it's about ionizing air in between the aircraft and the radar which can be done by RF emitters. EM radiation supposedly is absorbed by the layer. If this technology really works as some say it is a most important development. For example it could allow at least some degree of LO without recourse to expensive or delicate coating or to ultra high precision machining/matching of aircraft structures.

Am I missing something?

 

[StobieWan]

I'm surprised that there isn't more talk about plasma stealth. Based on what I've read it's about ionizing air in between the aircraft and the radar which can be done by RF emitters. EM radiation supposedly is absorbed by the layer. If this technology really works as some say it is a most important development. For example it could allow at least some degree of LO without recourse to expensive or delicate coating or to ultra high precision machining/matching of aircraft structures.

Am I missing something?

It'd be a two way thing - you'd be flying deaf and blind.

I've heard it talked about constantly with reference to various Russian systems but they're very visibly pursuing a fairly standard path of RCS reduction, which in itself should tell you all you need to know.

 

[Todjaeger]

It'd be a two way thing - you'd be flying deaf and blind.

I've heard it talked about constantly with reference to various Russian systems but they're very visibly pursuing a fairly standard path of RCS reduction, which in itself should tell you all you need to know.

It is also worth noting the issues some of the hypersonic systems are having with respect to guidance and telemetry. Due to the high speeds and the interaction with and effect hypersonics have on the atmosphere around them, a 'plasma stealth' field basically gets generated around the vehicle. As a result the test vehicles have apparently been getting blinded and the monitoring systems have been losing comms and telemetry links, which has been causing merry havoc in testing.

-Cheers

 

[ngatimozart]

It is also worth noting the issues some of the hypersonic systems are having with respect to guidance and telemetry. Due to the high speeds and the interaction with and effect hypersonics have on the atmosphere around them, a 'plasma stealth' field basically gets generated around the vehicle. As a result the test vehicles have apparently been getting blinded and the monitoring systems have been losing comms and telemetry links, which has been causing merry havoc in testing.

-Cheers

Does this 'plasma stealth' effect operate right across the EM field? I was just wondering because of the blind and deaf comment. Visible light is at a extremely high frequency (400 - 789 THz) and at the extremely short wavelength (380 - 750 nanometres). This would be LOS but would it be possible to use lasers as the medium to pass sensor and control data through the effect?

 

[AlfaSigma]

Ok about the self blinding but even used intermittently, directionally and in conjunction with other techniques it would be a great advantage. Breaking the contact and moving is all you need to survive. Network many platforms and you have a formation that while moving, intermittently hide, sense, communicate and fire. How do you defend against that?

Also not for every system, blindness would be a limitation. Ballistic and inertially guided terminal systems don't present an obvious and essential need to sense or communicate.

Another thing that comes to mind is that this technology gives the advantage to the offense over the defence. As such it is destabilizing.

If it works to any decent degree plasma stealth is a major thing. Probably the reasons why it's not talked about much are the newness and its high importance.

 

[Bonza]

If it works to any decent degree plasma stealth is a major thing. Probably the reasons why it's not talked about much are the newness and its high importance.

Actually I think the "if it works" part is probably one of the more significant reasons, because I haven't seen anything to indicate it actually does work, at least not in the manner referred to as a system for enhancing an aircraft's LO properties. There's obviously some significant practical issues with creating a buffer zone of ionised air around an aircraft moving at hundreds, or perhaps thousands, or kilometres per hour.

And the idea anyway is not entirely new, do some googling, it's been talked about for some time. Personally I think it's more the practical issues that mean it's not frequently discussed around here, or when it is, is greeted with some skepticism.

 

[gf0012-aust]

There's obviously some significant practical issues with creating a buffer zone of ionised air around an aircraft moving at hundreds, or perhaps thousands, or kilometres per hour.

And the idea anyway is not entirely new, do some googling, it's been talked about for some time. Personally I think it's more the practical issues that mean it's not frequently discussed around here, or when it is, is greeted with some skepticism.

.... and maintaining comms while said plasma bubble is generating....

 

[AlfaSigma]

I assume the Russian system creates a zone of ionization some distance away from the platform and in a specific direction based on the fact that the RF emitter takes up a very small area on the aircraft's skin. In this case the comms limitations would subsist only in that direction and I don't see how its operation would be affected by aircraft speed.
Those problems would present themselves in other approaches, like for example attempts to manage the field that naturally occurs at hypersonic speed or to create one that wraps close around the airframe.

In any case if the field can be turned on and off at will, the technical level limitation of a platform to comms and sensing in RF could be overcome at the operational level by having many platforms integrated alternating functions.

 

[gf0012-aust]

I assume the Russian system creates a zone of ionization some distance away from the platform and in a specific direction based on the fact that the RF emitter takes up a very small area on the aircraft's skin. In this case the comms limitations would subsist only in that direction and I don't see how its operation would be affected by aircraft speed.
Those problems would present themselves in other approaches, like for example attempts to manage the field that naturally occurs at hypersonic speed or to create one that wraps close around the airframe.

In any case if the field can be turned on and off at will, the technical level limitation of a platform to comms and sensing in RF could be overcome at the operational level by having many platforms integrated alternating functions.

the comms issues are not about how fast the plane is travelling

any ionisation forward of the skin does not create a "standoff delta" where you can magically transmit through that delta vacuum.

 

[PhysicsMan]

Does this 'plasma stealth' effect operate right across the EM field? I was just wondering because of the blind and deaf comment. Visible light is at a extremely high frequency (400 - 789 THz) and at the extremely short wavelength (380 - 750 nanometres). This would be LOS but would it be possible to use lasers as the medium to pass sensor and control data through the effect?

It does not operate in the whole spectrum, just the part that excites the plasma. It happens to be the range in which the targeting radars work. The energy plasma responds to can be tuned (within the same wavelength range, pretty much) by changing the plasma constituents (=source gases).

 

[PhysicsMan]

Actually I think the "if it works" part is probably one of the more significant reasons, because I haven't seen anything to indicate it actually does work, at least not in the manner referred to as a system for enhancing an aircraft's LO properties. There's obviously some significant practical issues with creating a buffer zone of ionised air around an aircraft moving at hundreds, or perhaps thousands, or kilometres per hour.

And the idea anyway is not entirely new, do some googling, it's been talked about for some time. Personally I think it's more the practical issues that mean it's not frequently discussed around here, or when it is, is greeted with some skepticism.

It works, no doubt about that. As you said, practical issues...
Also, it's a misconception that the plasma would be created from the surrounding air. It most likely will not be the case. There's no need to rely on the unpredictable air around. Besides, they will want to tune the plasma to the wavelengths of their choice, so they will use on-board gases instead, with the exact properties they want.

 

[PhysicsMan]

the comms issues are not about how fast the plane is travelling

any ionisation forward of the skin does not create a "standoff delta" where you can magically transmit through that delta vacuum.

Plasma boundaries are fairly precisely confined, so it shouldn't be a problem to devote a plasma-free area on the plane's surface for the transmission.

 

[gf0012-aust]

Plasma boundaries are fairly precisely confined, so it shouldn't be a problem to devote a plasma-free area on the plane's surface for the transmission.

if you create a comms friendly pocket on the boundary then any half decent spectrum interrogation process will probe and find.

you don't need much to detect a spike in the boundary. there's been a fairly solid review and remapping of affected spectrum in the last few years. hard to hide and not difficult to trace anomalies - esp with some of the smart AI developed in recent years that probes those waveforms.

 

[AlfaSigma]

the comms issues are not about how fast the plane is travelling

any ionisation forward of the skin does not create a "standoff delta" where you can magically transmit through that delta vacuum.

We are not understanding each other.

Does anybody know how the Russian system actually operates?

 

[PhysicsMan]

if you create a comms friendly pocket on the boundary then any half decent spectrum interrogation process will probe and find.

you don't need much to detect a spike in the boundary. there's been a fairly solid review and remapping of affected spectrum in the last few years. hard to hide and not difficult to trace anomalies - esp with some of the smart AI developed in recent years that probes those waveforms.

In that case it will be challenging to resolve the comms issue. The plasma can't be turned on-off very quickly so that they could send a signal out in a fraction of a millisecond and have it back on immediately. A possible solution is to use a different EM spectrum range that doesn't get absorbed (longer wavelengths).

 

[PhysicsMan]

We are not understanding each other.

Does anybody know how the Russian system actually operates?

The air speed won't affect plasma operation if it's not exposed to air. They could have it flow inside a cavity of some sort surrounding the plane.

 

[My2Cents]

The air speed won't affect plasma operation if it's not exposed to air. They could have it flow inside a cavity of some sort surrounding the plane.

Could you explain this better? It sounds to me like you are proposing to have an outer skin that keeps the air away from the plasma, then the aircraft inside the plasma. Don’t think that would work, even if we could engineer it.

 

[lopez]

Well you could do it but dont expect the plane to fly...

 

[PhysicsMan]

Could you explain this better? It sounds to me like you are proposing to have an outer skin that keeps the air away from the plasma, then the aircraft inside the plasma. Don’t think that would work, even if we could engineer it.

Why not? The plane wouldn't work or the plasma? Both should be fine, in theory. The cockpit glass is radar transparent, is it not? That's an example of a material that could be used as a thin outer hull. Not very bullet proof, but neither are the current RAM coatings. As for the plasma itself, it usually needs vacuum to function well, so if vacuum is created inside the cavity, the plasma can flow quickly and "coat" the plane. Also, it would probably make sense to break it into separate blocks, each with its own plasma generators and isolated from others. Messy, but nothing about that is a show stopper, just too difficult to implement.

 

[My2Cents]

Why not? The plane wouldn't work or the plasma? Both should be fine, in theory. The cockpit glass is radar transparent, is it not? That's an example of a material that could be used as a thin outer hull. Not very bullet proof, but neither are the current RAM coatings. As for the plasma itself, it usually needs vacuum to function well, so if vacuum is created inside the cavity, the plasma can flow quickly and "coat" the plane. Also, it would probably make sense to break it into separate blocks, each with its own plasma generators and isolated from others. Messy, but nothing about that is a show stopper, just too difficult to implement.

Let’s start a list of the problems:

1. The outer hull has to standoff from the inner hull, and is therefore the de facto airframe,you’re your aerodynamics have gone to hell. Wing thickness is increased 2x the standoff distance and you have lost most of your lift and massively increased frontal resistance, if you can get off the ground at all.
2. No coverage over air intakes and exhaust. One appeal of ‘plasma stealth’ is that it is supposed to cover these areas.
3. Requires large hatches operable in flight for weapons bays, gun, cockpit, and refueling. The entire outer hull will have to be easily and quickly to remove and reattach for normal maintenance.
4. The cockpit canopy is a laminated plastic composite, not glass. Materials limitation:
   • Low impact resistance. Bird strikes happen, they just are not usually a problem unless it is the engine intake of cockpit canopy. Now it is the whole aircraft.
   • Material is a plastic, which means it is subject to permanent distortion from normal continuous loads (very low yield strength). Low tensile strength (relative to normal materials) requires small sections or large thicknesses.
   • Temperature limit bars use on leading edges, engine intakes, and engine exhaust.
5. Supporting structure for the outer hull as a source of discontinuities in plasma coverage and independent source of reflections.
6. Very high loading on all panels (14.7 psia / 1 bar at sea level) plus aerodynamic loads. Thickness will be MUCH greater than for cockpit canopy. In flat surfaces material will be under tension instead of compression.
7. There is much more, but I am too tired to keep list them.

So, NO the plane won’t work, and probably not the plasma either.