A project of MHD manipulation for students
An MHD project
November 3, 2004
Continuously, students, young people, ask me for TIPE or even with the desire to set up an MHD experiment. Recently, an electronics engineer asked me for advice on building a flux compression generator, of the type of Sakharov (1952). I said no, because this toy was equivalent, in MHD, to a gun, and military things and me, it's been a long time, very long time, that we have nothing to do with each other.
For the same reason, I refused to teach in the field of bi-temperature plasmas and their numerous and formidable instabilities. My knowledge (and my skills) in this field are important and unique in Europe. Only Americans and Russians know what I know. And they know much more, having had the opportunity to develop research for thirty years. I refused to put this knowledge on my website, to make a book or even to give lessons in a Grand Ecole. It is a definite "no" in all aspects. The information given in "UFOs and American secret weapons" should not mislead. If the basic principles are there, I omitted to give the keys ensuring the feasibility of any project.
French military finally understood that "cold plasmas", bi-temperature (where the temperature of the free electron gas significantly exceeds that of the atom or molecule gas) represent an essential step for the development of many weapons and in particular for crossing the Heat Wall, for positioning shooting platforms at intermediate altitudes (30-150 km). There are these applications, and many others. However, the French have been absent from this field for thirty years. These plasmas are as different from fusion plasmas or stellar plasmas as liquids are from gases. So, for years, people, "civilians", have been sent to me, who would be ready, "out of pure scientific interest", to fund MHD research. I can no longer count the number of people who have been stuck to me since 1975. I will only talk about the two last ones. The first was of Italian origin. Creative, had set up and run a study office, "had just retired and had fresh money, he said". But people always let out something too much. This one had worked on the development of a helicopter pilot's helmet where, to aim at a target, it was enough to turn the head. Mercury circuits, integrated into the helmet, played the role of semicircular canals, informing the fire computer of the helmet's position and the point of aim.
Once you have had "small army contracts", it is rare that you lose contact. The industrialist, in the middle of the eighties, paid Bertrand Lebrun during the year when he finished writing his thesis before we closed our business, was machining ... tank turrets in his large workshops, with vertical lathes. I had noticed it from my first visit to him. These damned turrets should have been hidden in machining.
Every time a guy shows up, I do an investigation on him. A couple of years ago, it was the young director of a food industry company who contacted me. Another "who was passionate about MHD". I agreed to provide a project and I was paid six months as a consultant engineer on it. In this food industry activity, they fully used the possibilities offered by microwaves. The man immediately told me "you know, if you have any idea, here we can realize it. There is space and solid technical support".
He did not expect the dirty joke I was going to play on him, and it will be the subject of the project I am going to describe here. It is an application of MHD of which I really do not see how one could draw a military application (although, as Raymond Devos would say ... maybe with liquid metals, or oxides in solution, to do isotope enrichment, who knows?).
The machine I am going to describe is a very simple MHD pump, powered by solar energy. Its efficiency is incredibly bad, absolutely abominable, especially since it would be designed to work with fresh water, even pure water, whose electrical conductivity, everyone knows, is absolutely miserable.
But then, why do it?
To pump, very slowly, over hours, day by day, water from ponds, wells, water points and to purify this water by burning bacteria, parasites, etc., with the oxygen released by electrolysis. No moving parts, no maintenance, nothing. You set it up, you direct the sensors towards the sun, you install the water intake and return pipes and you let it run. In the end, the least drinkable water will become biologically pure. It was a nice project, cheap. It could have interested UNESCO or other similar organizations. It was clear that it would not compete with the pollution control systems used for pools, in hospitals, effective, simple and based on UV bombardment. The quality of this MHD system was its fantastic simplicity.
Six months passed. I provided all the data. It turned out that permanent magnets had made solid progress in 30 years, even in the civil sector. One to two teslas, instead of less than a tenth. Here is the plan of the pollution control cell:
MHD Pollution Control Unit
It's a setup, but you can imagine ten different ones in the hour that follows. I chose this one because it is a system that we had actually tested (Figure C) in 1976, in the basements of the Marseille Observatory where Viton and I had set up a lab "where the future already belonged to the past", paraphrasing the famous English "muppets". At that time, we had magnets developing 900 Gauss (0.09 tesla), toroidal shape, square cross-section. The direction of the field is indicated. We added the principle of the parietal accelerator whose advantage is to be able to reduce as much as desired the distance between two electrodes, which is appreciated when working with a fluid with very low electrical conductivity (fresh water). But before considering things from this angle, you can take two strong magnets (our magnets had an overall diameter of 8 cm and a square cross-section of 15 mm by 15 mm). You glue them "nose to nose" with superglue, putting two north faces, or south, it doesn't matter, facing each other. For the electrodes, we simply fixed two 2 mm diameter red copper wires to the clamp. Put everything in a basin filled with salt-saturated water and connect the wires to a battery. You get a very nice centrifuge.
In practice, it would be necessary to have magnets in the form of thin disks. Maybe 2 mm thick, or a few millimeters. On these magnets, electrodes fixed in a ring. Material: not sensitive to oxidation, corrosion. Effect: to rotate the water. On the other side: inclined vanes that transform this rotational movement into axial movement. The desired effect is mainly electrolysis. All of this is worth trying, as well as the effect on a medium polluted by bacteria. A nice, inexpensive job, within the reach of any engineering school or technical school. Beyond that, obviously, it is necessary to aim for the use of magnets developing at the most ...