Manetohydrodynamics/Electrodynamics and our future of flight

here is a great source cited video that is fun and very interesting/informative.



here is a photo of the shuttle glowing with ion's of singlet oxygen, meaning a very reactive single atom of oxygen rather than the normal O2/


even in what we call low earth orbit there is a staggering amount of ambient power and large magnetic fields provided by out earth and even more so the sun.

using these effects in combination the term drag and drag heating become meaningless allowing hypersonic and above in earths atmospear and even more so in space.

imagine using the magnetic force of the earth or the sun to push you along rather than some rocket engine


Why is this tech always pushed to the side or in to da4rk areas of research?

the tic tac would make a perfect electrodynamic craft.


we know our 'secret' space plane has been testing verious means of thrusters, wonder if something like this was tested.



using the highly ionized gases in near space and the heavy ions from the sun would provide a means of almost unlimited fuel for these craft.


makes you wonder.

Nicola Tesla says Hold my beer. a reply to: ifo8844

originally posted by: ifo8844
here is a great source cited video that is fun and very interesting/informative.

It's not a great source, I thought it was awful. The guy reads enough from wikipedia but he fails to read these most noteworthy comments about use in earthly applications:

Magnetohydrodynamic drive

Few large-scale working prototypes have been built, as marine MHD propulsion remains impractical due to its low efficiency, limited by the low electrical conductivity of seawater. Increasing current density is limited by Joule heating and water electrolysis in the vicinity of electrodes, and increasing the magnetic field strength is limited by the cost, size and weight (as well as technological limitations) of electromagnets and the power available to feed them.[13][14]

Stronger technical limitations apply to air-breathing MHD propulsion (where ambient air is ionized) that is still limited to theoretical concepts and early experiments.

The video completely fails to even mention these limitations and leaves the viewer with the impression that practical MHD vehicles operating in Earth's atmosphere might be around the corner (although the astute viewer would be suspicious that not even a prototype vehicle of such is shown, just cute animations).

He says virtual particles are misnamed because they are just like regular particles except shorter-lived, while physicist Matt Strassler says virtual particles are misnamed because they aren't like real particles at all.

A virtual particle is not a particle at all. It refers precisely to a disturbance in a field that is not a particle.

The video also mentions spacecraft applications. MHD and many other technologies are potentially viable in spacecraft that may not be viable in Earth's atmosphere for numerous reasons.

a reply to: ifo8844

Fascinating. I will return later so I can watch the vid.

Thankyou for a good thread with words and opinions and that is cool.

I've always felt, "it has to be so easy" about so many things in life like this, but I also learned along the way, a good magician never sells his best tricks.

originally posted by: Arbitrageur
It's not a great source,...

New to me, so any source as a connection and landing point to something new IS a great one, regardless of initial credibility imo.

To know bad is to understand truth.

Thanks for expanding on information in the thread too, I won't ignore it, regardless.

a reply to: Arbitrageur

the sources cited and shown in the video


i mean unless JPL doesn't pass your smell test.

even Einstein was a Patient Clerc at one point.


and im always open to new and refreshing ideas how's these craft move around and as they are officially known to the US Government 'Trans Medium Objects', going from space to air to water and back is a neat trick and not something we can do yet here on earth, as far as i know no human craft that is going faster than the speed of sound but leaving no sonic booms or being flattened to foil when it enters the water at 100's of MPH come back out and go hypersonic to space in one flight.


We might not have all the i's dotted and the t's crossed but i would bet you these theories of movement will get us futher in time than any rocket or jet.


If they haven't already

Yeah id go with Arbitrageur's response in that the video didn't actually say very much, and tried to repeat itself lots of times to bulk out the information. Also the context is misplaced as though we are just on the cusp of the technology when the reality is quite different.

Research does appear to suggest that in water, its impractical at least in sea water, but then the challenges become even greater in air largely due to the lower density of the air among other things.

So then the idea of pushing against quantum vacuum... yeah run that by me again? When people invoke two two words together they almost ultimately are going for word salad to wow the viewer more than saying anything.

Also - Particle Physicist here and just as relativity and relativistic speeds are so misunderstood by people with the old "You cant get to the speed of light because your mass becomes infinite" total uuuugh non-sense (E=MC^2 is a simplification of E^2 = P^2C^2 + M^2C^4 written as E=gMC^2 where people say "the g increases them M" when that wasn't the point at all. its simply that you need infinite momentum. Virtual particles are so often abused. Their existence if at all requires acceptance of quantum electrodynamics and they DO NOT exhibit the same properties as regular particles. They are in an absolute way governed by the uncertainty principle

dE dt > hbar/2

When we talk about interactions mediated by virtual particles this is quite important. It kind of states that you can borrow a certain amount of energy, so long as you give it all back within a certain amount of time in order to mediate an interaction. The virtual part of this process REQUIRES conservation of quantum numbers/properties. You do not interact with a closed loop virtual particle/anti-particle system for free.

Even things like the Casimir effect have explanations that do not require virtual particles.

Also any experiment conducted on earth will by no means be done in vacuum. The best vacuum produced on earth is nowhere near that of deep space, and even deep space is not total vacuum. I guess the point i am making is that, when someone says these things in the context of propulsion it makes me sigh, since there is usually a lot of want to believe and not much will to look at reality.

I also wish people wouldn't say things like "There is a lot of energy we can harness from the Earths magnetic field"

In space Earths magnetic field is in the 10-30s of micro-tesla range... its tiny. magnetic tape sitting against the tape head is about the same strength (ok sure at that distance) A neodymium magnetic is typically 1-2 Tesla.

Sure the field strength falls off with the cube of the distance (not the square) so the earths field is not nothing, but it's not going to beat gravity by a long shot still.

originally posted by: nerbot

originally posted by: Arbitrageur
It's not a great source,...

New to me, so any source as a connection and landing point to something new IS a great one, regardless of initial credibility imo.

To know bad is to understand truth.

If you want to see a demonstration of the principle, I think a video like this which shows a simple experiment is how we all learn better, and since it's a real experiment, we don't have to worry whether it might be misleading, like some animations can be misleading. As he says at the end of the video, "It's not super-great, but it does indeed work" which might be an apt summary of the experiment.

The Magnetohydrodynamic Drive uses the magnetic force to push water.


The principle is indeed a sound scientific principle, but you can also get a feel for how much water is moved and how fast, which is not much and not very fast.

Of course anything can be scaled up but part of the art and science of engineering is weighing all the different alternatives available and deciding which alternatives best meet the design objectives, including initial cost, maintenance cost, operating cost, power, efficiency, and other design objectives. The internet is flooded with a ton of ideas these days about things that work, but are not very practical from an engineering perspective meaning in some way the idea has problems with cost/efficiency/practicality. It is apparently hard for the layperson without an engineering background to sort these things out because I see people latch on to terrible ideas all the time not realizing why they are terrible ideas.

Part of the reason some ideas are terrible, is not necessarily because it doesn't work at all, but maybe it works not that well and there are better alternatives which work a lot better. I'd say that seems to currently be the case with MHD propulsion in Earth's atmosphere or in the ocean.

The youtuber Thunderf00t does a pretty good job shining some light on the practicality of some of these ideas of things that "do indeed work" but are not "super great". I don't agree with him 100% but probably 98% of the time I do. If someone was conning investors trying to get them to invest in MHD aircraft he might do an "MHD propulsion: BUSTED" video, but to my knowledge it hasn't got that far yet. He made a great video on "solar freaking roadways". Yes solar panels work and they can be put on the road (a small experiment has done this), but I'm amazed it's not immediately obvious why it's not a good idea as promoted, and it took a video from thunderf00t to explain it to many people.

originally posted by: ErosA433
So then the idea of pushing against quantum vacuum... yeah run that by me again? When people invoke two two words together they almost ultimately are going for word salad to wow the viewer more than saying anything.

It won't make any more sense the second time they run it by you, but if you didn't know physics it might sound cool. Since you do know physics, it's likely apparent to you the narrator doesn't understand the topic, as it was apparent to me.

NASA was open-minded enough to consider that the laws of physics might need some revising when they thought they were measuring propulsion from the infamous "EMdrive" which was said to do something like that.

EmDrive

In 2014, White's first conference paper suggested that resonant cavity thrusters could work by transferring momentum to the "quantum vacuum virtual plasma", a new term he coined.[6] Baez and Carroll criticized this explanation, because in the standard description of vacuum fluctuations, virtual particles do not behave as a plasma; Carroll also noted that the quantum vacuum has no "rest frame", providing nothing to push against, so it can't be used for propulsion.

So Harold "Sonny" White had a hypothesis, which wasn't well received, and some apparent thrust was measured. But after further analysis, it appears the prediction of the current laws of physics that the EM drive was impossible and the measured "thrust" was an anomaly of the experimental setup appears to be correct.

In 2016, Harold White's group at NASA observed a small apparent thrust from one such test,[13] however subsequent studies suggested this was a measurement error caused by thermal gradients.[14][15] In 2021, Martin Tajmar's group at the Dresden University of Technology replicated White's test, observing apparent thrusts similar to those measured by the NASA team, and then made them disappear again when measured using point suspension.[1]

No other published experiment has measured apparent thrust greater than the experiment's margin of error.[16] Tajmar's group published three papers in 2021 claiming that all published results showing thrust had been false positives, explaining each by outside forces. They concluded, "Our measurements refute all EmDrive claims by at least 3 orders of magnitude."

Yeah the EM drive stuff came to mind, which, if memory serves correctly, the thrust was extremely low and was either within systematic uncertainties on the equipment and or interplay between equipment couldn't be ruled out? That or its in line with basically photon thrust from momentum carried by the IR radiation?

They did want to test it, did so, and yeah it went quiet, not because its some kind of dark secret tech but because when tested it turned out to be kinda a null starter.

a reply to: ErosA433
Ion drive was tested in experiments on one of the X37-b off memory..Good for satellites and smaller space vehicles.

a reply to: Blackfinger

The ION drive is actually useful, the EM... i dont think so much