Of course it was solved. NASA did this plane with ultra long very spiky nose. If you think of Concorde's nose, than 3-4 times longer.
No.
1.) That plane hasn’t been built:
NASA hands massive supersonic contract to Lockheed Martin, with one catch: No sonic boom
2.) It reduces the sonic shockwave by half – it doesn’t eliminate it.
As I said plasma project by Soviets was abandoned because it would make plane glow and be visible without radar. It turned out not to be solution, so there is no point offering it to military, because they know about it.
Here is Wikipedia article on plasma stealth:
Plasma stealth - Wikipedia
We're not talking about radar invisibility, so this stuff is irrelevant.
In Wikipedia article there is only little about canceling drag and possibly sonic boom with plasma.
There's nothing about sonic booms on
that Wikipedia page. And plasma can reduce drag; it doesn't cancel it. At Mach 31 that's an important distinction.
But there is this US company that patented technology based on the same principles:
Plasma Stream | Drag reduction technology
They're reducing drag on shipping trucks by preventing vortexes from forming behind the truck trailer, big deal.
AAVs darting across the sky at 24K mph with no plasma trail is an entirely different situation.
Your model is wrong. Meteors consist of variety of organic and inorganic compounds. When meteors heat up in atmosphere these compounds start turning into gas and that gas is what you see as a tail. It's a plasma but it is not bonded to the meteorite, just loose material falling off.
Your understanding is wrong. You don't need any material to be emitted from a hypersonic object moving through the atmosphere to see the blazing trail of plasma that it makes as it moves - that's why craft like the Space Shuttle look like a meteor upon re-entry: the rate of motion through the atmosphere compresses the air, heating it to incandescent temperatures, which leaves a long trail of glowing plasma behind the craft:
"Why does this happen? The air gets heated by the Orbiter’s ramming the atmosphere at 20+ times the speed of sound. And contrary to popular belief, it’s not friction that heats the air, but compression. When you compress a gas it heats up (like when a bicycle pump gets hot when you use it a lot), and the Orbiter is screaming through the atmosphere at hypersonic speeds. That compresses the air a lot. A shock wave forms in front of the Orbiter, and the air begins to glow as it gets heated up to temperatures as high as 1260° C (2300° F)."
Source:
The fiery descent of Atlantis... seen from space! - Bad Astronomy
AAVs move at those velocities yet produce no such trail of superheated incandescent plasma in their wake. You're suggesting creating plasma on the surface of the craft to reduce the atmospheric drag. But to reduce the drag that much, at those speeds, would require the production of the same kind of superheated plasma, which would also leave a trail behind the craft. So your solution solves nothing, and doesn't explain this signature performance characteristic of AAVs. But my explanation does.
Contrary to that plasma on UFO is bonded by strong electric field. That bond prevents plasma from forming tail.
You can't "bond" plasma to a craft with an electric field because plasma has a net zero electric charge: it's composed of both positive and negative charges in equal measure. All you can do is continually convert the atmospheric gas into plasma and let it flow away.
Even the flow of plasma is notoriously difficult to control with any precision. That's why we don't have fusion reactors powering our energy sector right now: it's the most unstable and chaotic form of matter.
I hate this "plasma solves everything!" kick that you're on right now. It may be one factor - perhaps AAVs do use it for radar stealth, for example. But I can't see how it explains any of the key performance characteristics of AAV propulsion, ranging from radical accelerations to silent hovering directly over eyewitnesses with no downward air movement, to hypersonic motion with no sonic boom or visible propulsion signature of any kind, and it sure as hell can't explain interstellar travel.
Plasma is not a magic bullet that can explain the key signature performance characteristics of AAVs. Magnetoaerodynamics can be used for propulsion purposes, but it's really just another primitive application of reaction propulsion, and therefore unsuitable as an explanation for the most common types of AAV maneuvers. Gravitational field propulsion, on the other hand, explains all of the key performance characteristics of AAVs perfectly. No other explanation even comes close to doing that.