Daumic

It seems that you contest my explanation of the effect of magnetic shield on an electric coil. Do you think that the magnetic shield has no effect on the coil?

These documents are interesting but each one uses a principle of propulsion different of that which I propose. https://en.wikipedia...i/Magnetic_sail The magnetic sail or magsail is a proposed method of spacecraft propulsion which would use a static magnetic field to deflect charged particles radiated by the Sun. https://en.wikipedia...i/Electric_sail The electric sail (also called electric solar wind sail or e-sail) is a proposed form of spacecraft propulsion using the dynamic pressure of the solar wind as a source of thrust. http://engineering.d.../Winglee_00.pdf http://science.nasa....000/ast04oct_1/ The mini-magnetospheric plasma propulsion uses the interaction between solar wind with magnetic bubble generated by injection of plasma in the magnetic field of a coil. The electromagnetic sail that I propose use the Laplace force applied to an electric current by the geomagnetic field. The concept nearest of this idea is the electrodynamic tether: https://en.wikipedia.org/wiki/Electrodynamic_tether

For me, the problem is here: the fact that a part of the loop is covered by the shield forbids any argument about a flux through the loop. The concept of magnetic flux through a conducting loop is valuable only in the case where the magnetic induction acts on the whole length of the loop.

An energy source is necessary The electric current in a superconductor circulates without loss of energy. Can one imagine that an electromagnetic sail can go in space without energy source other than that necessary to the starting of the electric current? In fact, not, an energy source is necessary for the electromagnetic sail because its displacement in the terrestrial magnetic field generates an electric counter voltage in the superconductor that cancels the electric current. An energy source is necessary to maintain the electric current in the electromagnetic sail during space launching. The Laplace force in the electromagnetic sail is: F = I. B. L With F: Laplace force applied to the higher part of the circuit, I: intensity of the electric current, B: horizontal component of the terrestrial magnetic field, L: length of the higher part of the circuit. If the circuit moves at the speed v, it will appear a counter voltage: U = B. L. v With U: counter voltage applied to the higher part of the circuit, v: speed of the circuit in the magnetic field. The power p needed to maintain the electric current is: p = I. U This electric power can be still expressed by: p = (F / B. L ). ( B. L. v ) = F. v The needed electric power is exactly the upward mechanical power.

The magnetic shield described in the two articles cited in my first message is made of two layers: a layer made of ferromagnetic material, a layer made of superconductive material. It is true that the ferromagnetic layer increases the magnetic induction inside the shield. But the superconductive layer creates an opposed magnetic induction so the shield stops the magnetic field generated by the ring current. This effect of the shield on the inner magnetic field is not the more important. The more important effect of the shield is the neutralization of the outer geomagnetic field on the part of ring current covered by the shield. This neutralization, made by the superconductive layer of the shield, permits the dissymmetry of the Laplace forces applied on the ring current and the movement of the whole sail.

The electromagnetic sail as space launcher If this electromagnetic sail is possible, I see it as a space launcher. The terrestrial magnetic field extends to several thousands kilometers from ground. It could thus provide a support to an electromagnetic sail until in orbit. To obtain an effective sail, the material constituting the conducting ring must carry the electric current most intense possible. The best choice for this material is a superconductor. To ensure that this superconductor can be used for an electromagnetic sail, the minimal condition is Laplace force that is applied to it higher than its weight. Following simple calculation shows that two criteria are significant to satisfy this condition: the critical current density that can carry the superconductor and its density. Criteria of the superconductor for an electromagnetic sail Let a conducting square circuit located at the terrestrial equator. The circuit is orthogonal to the terrestrial magnetic field. The direction of the electric current is such as Laplace forces are directed towards the outside of the circuit. The forces applied to the western and eastern parts of the circuit cancel each other. The low part of the circuit is coated with the magnetic shielding described in my first message and thus does not undergo Laplace force. The high part of the circuit undergoes a Laplace force that is not compensated. What should be this Laplace force to support the weight of the whole circuit? F = I. B. L With F: Laplace force applied to the higher part of the circuit, I: intensity of the electric current, B: horizontal component of the terrestrial magnetic field, L: length of the higher part of the circuit. P = 4. d. v. g With P: weight of the whole circuit, d: density of the circuit material, v: volume of the higher part of the circuit, g: acceleration of terrestrial gravity. It is necessary that: F > P I. B. L > 4. d. v. g With s: section of the circuit, j: density of the electric current. j. s. B. L > 4. d. g. s. L j. B > 4. d. g Finally, to obtain a Laplace force higher than the weight, it is necessary that: j > 4. d. g/B The current density that the superconductor must carry to be used in an electromagnetic sail depends on its density and the ratio g/B. First criterion: density of the superconductor Among all known superconductors, it seems to me that the magnesium diboride shows the most interesting characteristics: a low density of 2.57 g/cm3 and a critical current density of 10000 A/mm2 (3). MgB2 seems to satisfy the minimal condition to constitute an electromagnetic sail. For example, in a horizontal magnetic field of 40 µT, the density of current necessary to ensure that the Laplace force equalizes the weight of a square circuit of MgB2 is 2520 A/mm2, level much lower than the critical current density of material. To obtain a complete electromagnetic sail, it remains to add the mass of the magnetic shielding and especially the mass of the cooling system because the magnesium diboride becomes superconductive only below 40 K. Second criterion: the ratio g/B The Internet site (4) calculates the parameters of the terrestrial magnetic field anywhere on the terrestrial sphere and in altitude. It shows that the horizontal component of the terrestrial magnetic field, the only usable for a space launching, is maximum at the equator. The acceleration of terrestrial gravity g also varies according to altitude. The following mathematical formula (5) calculates g: g(h) = g0/(1 + (2h/R) + (h2/R2)) With g0: acceleration of terrestrial gravity to altitude 0, g(h): acceleration of terrestrial gravity to altitude h, h: altitude, R: terrestrial radius. The following table shows the variation of the magnetic field and terrestrial gravity according to altitude: The data of this table are shown in the following graph: These data show that the magnetic field decreases more quickly than the acceleration of terrestrial gravity when altitude increases. The g/B ratio thus increases with altitude. This ratio determines the effectiveness of the electromagnetic sail. The propulsion force of the electromagnetic sail decreases with altitude. As the electric current in the superconductor cannot exceed the critical current, there is a limit altitude beyond that the sail ceases working. (3) http://iopscience.iop.org/article/10.1209/epl/i2002-00479-1/meta;jsessionid=E3DÇ22DC2891E013CCDD261AE163683.c1 (4) http://www.geomag.bgs.ac.uk/data_service/models_compass/igrf_form.shtml (5) http://e.m.c.2.free.fr/poids-and-gravitation.htm

The following image summarizes my idea. The electric conductor is red. The magnetic shield is blue.

The article “A Magnetic Wormhole” cited in my first message describes an experiment where the poles of a magnetic field are separated by a magnetic shield. The magnetic field connecting the two poles is hidden inside the shield. This experiment shows that the magnetic shield is an efficient barrier for an inner magnetic field.

According to the articles cited in my first message, the magnetic field generated by the part of ring current covered by the shield remains confined in the shield. This confinement is obtained by the currents induced in the superconductive shell of the shield that create an opposed magnetic field.

Imagine a conducting square circuit located at the terrestrial equator. The circuit is orthogonal to the terrestrial magnetic field. The direction of the electric current is such as Laplace forces are directed towards the outside of the circuit. The forces applied to the western and eastern parts of the circuit cancel each other. The low part of the circuit is coated with the magnetic shield described in my first message and thus does not undergo Laplace force. The high part of the circuit undergoes a Laplace force that is not compensated. The shield is necessary to create a dissymmetry in Laplace forces. This dissymmetry permit the movement of the electric circuit.

Correction: in my first message, I speak about the Lorentz forces. The Lorentz forces concern the action of a magnetic field on a charged particle moving. The Laplace forces concern the action of a magnetic field on an electric current. With the electromagnetic sail, we are clearly in the second case: Laplace forces. The external magnetic field is generated by an external electric current, for example the electric currents in the Earth’s core for the geomagnetic field. This external magnetic field generates Laplace forces on the part of the ring electric current no protected by the shield. This is action. The ring electric current generates also a magnetic field. A part of this magnetic field remains inside the shield. The other part of this magnetic field, produced by the part of electric current outside the shield, generates Laplace forces on the electric current generating the external magnetic field, for example the electric currents in the Earth’s core. This is reaction.

Yes, the shield is a barrier that insulates the inner volume from the external magnetic field.

A series of articles published recently (1) (2) described an effective shielding against a magnetic field. This effect is obtained by associating two concentric shells, one made of a superconductor, the other made of a ferromagnetic material. The shielding makes it possible to mask a volume from an external magnetic field or to dissimulate a magnetic field from the external world. It can in particular move away a magnetic pole from its opposite and thus to simulate a magnetic monopole artificially. Perhaps this magnetic shielding would make it possible to create an electromagnetic sail that means a system of propulsion which would use the natural magnetic fields, in particular the terrestrial magnetic field. Imagine a ring of electric current placed in this magnetic field. Lorentz forces that are exerted on the electric current cancel: no translation of the ring is possible. On the other hand, if part of this ring is taken in magnetic shielding described above, the action of the magnetic field on the electrical current in the masked section is cancelled. Lorentz forces that are exerted on the whole of the electric current do not cancel any more: the ring can be put moving. Is this sort of electromagnetic sail possible? (1) Gomory, F. et al. Experimental realization of a magnetic cloak. Science 335, 1466 (2012) (2) Prat-Camps, J. et al. A Magnetic Wormhole. Sci. Rep. 5, 12488; doi: 10.1038/ srep12488 (2015)

Cold Fusion and Branly effect In 1989, Pons and Fleischmann claimed to cause fusion in an ordinary electrolytic cell containing heavy water. This process is named Cold Fusion. It begins by the electrolysis of heavy water on a Palladium cathode that induces the penetration of Deuterium in the electrode. This penetration is sometimes associated with the release of an excess heat and the production of Helium and more rarely Tritium. Many scientists who tried to reproduce this phenomenon were disappointed by the absence of result. But some teams around the world persevered in the study of Cold Fusion. The team of Mosier-Boss (see P.A. Mosier-Boss, S. Szpak, F.E. Gordon, L.P.G. Forsley, Characterization of tracks in CR-39 detectors obtained as a result of Pd/D Co-deposition, in Eur. Phys. J. Appl. Phys. 46, 30901, 2009) has recently obtained interesting results with the detector Cr-39. The traces collected on this detector are convincing indices of nuclear reactions occurring in a cathode of Palladium during heavy water electrolysis. Numerous explanations, sometimes highly speculative, have been proposed. In the following message, I propose an explanation more classical. If this explanation has some reality, the Cold Fusion could be a hidden Hot Fusion. I think that the Cold Fusion could be related with Branly effect. A few years before 1900, the scientist Branly has discovered a phenomenon that has been used sometimes in radio communications. This phenomenon is the change of electric conductivity of a metallic powder by an electric current or an electromagnetic wave. The effect is reversible: a shock on the tube containing the powder restores the initial conductivity. During a long time, the explanation of this effect has been controversial. But recently some experiments give a complete explanation of the phenomenon (see E. Falcon, B. Castaing, Electrical conductivity in granular media and Branly's coherer: a simple experiment, in American Journal of Physics, vol. 73, pp. 302-307, 2005). The modern vision of this phenomenon is now: - the pellicular layer of oxide on each grain of the metallic powder gives an high electric resistance to the material, - the electric current flows through very small contacts between the grains, - the high density of current on resistive oxide layer melts the material by Joule effect and creates tiny metallic gates, - when the metallic gates are established, the resistance of the powder decreases considerably, - the resistive initial state of the powder can be retrieved by a shock on the tube containing the powder: the shock breaks all the tiny metallic gates between the grains. The Branly effect shows the possibility to concentrate easily the electric energy in a very small amount of matter. Knowing that, my vision of the Pons-Fleischmann effect is: - the electrolysis of heavy water on a Palladium electrode induces the penetration of Deuterium atoms in the metal, - the Palladium electrode is a polycrystalline material, a juxtaposition of little crystallites held together by a thin layer of amorphous material, - the accumulation of Deuterium atoms in the metallic lattice, particularly in the amorphous material between crystallites, reduces the conductivity of the metal, - in rare circumstances, this accumulation of Deuterium could create an insulating wall, - as the Branly effect predicts, the electric current perforates this resistive material through very small areas, - the high density of current in these tiny passages could generate hot spots, - in each spot, the interaction between the electric discharge and its own magnetic field could generates a dense and hot plasma, - this hot spot contains a great amount of Deuterium atoms, so some nuclear fusions could occur, - after that, the continuous flow of Deuterium atoms produced by the electrolysis restores the resistive state of the tiny volume where the fusion has occurred. This hypothesis could be verified by a Branly experiment conducted under a deuterated atmosphere. This experiment can take the form of a metallic powder heated in a Deuterium atmosphere. If the metal is Titanium or Palladium, the grains of the powder become covered by a layer of deuterated compound. This layer changes the conductivity of the powder that becomes resistive. If this deuterated compound is not sufficiently resistive, the treatment could be made with heavy water that can generate a deuterated hydroxide more resistive. What could be the comportment of this powder with a short pulse of high voltage? If the contact areas between the grains are very small, the density of electric energy in these tiny volumes when the current flows could perhaps generate hot plasmas. These short lived plasmas could permit some nuclear fusion between Deuterium nukes. It could occur in the entire mass of the powder a great number of these hot spots. After that, many metallic gates are established between the grains of powder, the electric current flows without resistance. A shock on the tube containing the powder breaks these tiny metallic gates and so the initial resistive state is restored for a new experiment.

These last years, the search for extrasolar planets has been successful. To date, the astronomers have detected more than 400 extrasolar planets. Among these 400 planets, only ten have been discovered by their own light. There is perhaps a phenomenon which could facilitate this search for extrasolar planets. The astronomer Michael Mumma and his team have discovered in 1981 (*) a natural laser emission produced by the Martian upper atmosphere. This very fine emission ray centered on 10,33 µm is due to carbon dioxide, majority component of the Martian atmosphere. This natural laser emission has been not only confirmed by other teams but another natural laser has been discovered in the Venusian upper atmosphere. In consequence of these discoveries, one can suppose that this phenomenon of stimulated emission generated by a planetary atmosphere is frequent. This phenomenon of stimulated emission could be used for the search for extrasolar planets. The direct detection of an extrasolar planet conflicts, with current technology, with a considerable obstacle: the difference of brightness between planet and its star companion. If the studied planet has an atmosphere and if this one presents a stimulated emission, the brightness of planet in the emission ray could be amplified considerably. To benefit from this emission, it would be necessary to detect very thin rays. With this condition, the ratio of brightness between star and planet could become more favorable for a direct detection. A first step in the use of this phenomenon could be the checking of its presence on the extrasolar planets already discovered. Several ray masers would deserve a detailed attention: the ray at 23.7 GHz emitted by molecule NH3 and the rays at 22 GHz and 1.66 GHz emitted by molecule H2O and radical OH. As the stars emit little in this part of electromagnetic spectrum, one can hope for a ratio of brightness more favorable for the planet detection. The ray maser of ammonia could be a good marker for gas giant planets. The masers of water and radical hydroxyl would be good indices for planets similar to Earth. (*): "Discovery of Natural Gain Amplification in the 10-Micrometer Carbon Dioxide Laser Bands one Mars: A Natural Laser"; MICHAEL J MUMMA, DAVID BUHL, GORDON CHIN, DRAKE DEMING, FRED ESPENAK, THEODOR KOSTIUK, and DAVID ZIPOY; Science, 3 April 1981, Vol. 212, No 4490, pp. 45 – 49.

Is it possible to test the sonofusion with the deuterium-tritium reaction? The research on sonofusion tries to obtain nuclear fusion in deuterated liquids. In a typical experiment of sonofusion, a beam of neutrons generates tiny bubbles in the liquid. An ultrasound field expands and contracts these bubbles. The nuclear fusion could occur when the collapse of bubbles is sufficiently fast to generate an intense shock wave. The last experiment of Rusi Taleyarkhan and his team has demonstrated the emission of neutrons in deuterated acetone. However the signs of reaction in this experiment were very feeble. With deuterated products, the possible reactions are: D + D > He3 + n D + D > T + H These reactions are not easy whereas the reaction between deuterium and tritium is the easier reaction of nuclear fusion: D + T > He4 + n If we could test the sonofusion with a mix of deuterium and tritium, the signs of fusion could be more evident. But the use of tritium is very expensive because it doesn't exist in nature. It must be generated by a nuclear reaction: Li6 + n > He4 + T Tritium is also a radioactive element. It must be manipulated with protection. So the test of sonofusion with the DT reaction obliges the use of a very small amount of tritium. A mean to limit the amount of tritium in a sonofusion experiment could be the use of tritiated tensioactive molecules. These molecules, dissolved in heavy water, could be like for example CH3-(CH2)n-phenyl-SO3 Na (alkyl-phenyl-sulfonate) where one or several hydrogen atoms are replaced by tritium atoms. When this sort of solution is exposed in sonofusion experiment, the neutron beam generates bubbles. These bubbles grow during the depressive phase of the sonic wave. What could be the comportment of tensioactive molecules? I propose two hypothesis: - the tensioactive molecule that encounters the surface of the bubble remains glued on this surface by its apolar part, - when the compressive phase of sonic wave occurs, the bubble surface drags the tensioactive molecules. By this way, a mix of deuterated water molecules and tritiated tensioactive molecules could be concentrated on the top of the shock wave in final collapse of bubble. If this scheme works, it could be possible to study the sonofusion of deuterium and tritium in heavy water. The synthesis of tritiated molecules is a standard technique, particularly for the biological research. Used as a radioactive marker, the tritium permits the study of chemical or biological reactions. A very small amount of tritium seems to me sufficient to start D-T reactions. Some calculations and hypothesis suggest that sonofusion with tritium could be tested with a solution of heavy water containing less than 100 micromoles of tritium per liter.