Let's remind in brief appointment and an activity principle the MHD-GENERATOR . It is an engine installation in which thermal energy of a working body (an electrolyte, liquid metal or plasma) will be conversed immediately to the electrical.


For magnetic field making in model ten school horseshoe magnets, combined by like poles closely to each other are used. In a medial part magnets are fastened by two aluminium plates. Plates are joined in three places (along the edges and in the middle) by bolts and nuts. Breadth of plates of 50 mm, a thickness of 1-2 mm. The extremities of plates are bent at right angle - so it will be more convenient to anchor them in pads of school laboratory supports.

As electrodes two copper plates in length about 300 mm, by breadth 20 mm and of 2 mm are used thickness. The upper extremities of these plates also are bent at right angle and anchored in pads of supports. To the plugs erected on electrodes, the school demonstration galvanometre is connected.


As plasma radiant the usual gas burner or the petrol burner Bartelja giving a vertical flame serves.
by preparation for demonstration erect electrodes in a gap between poles of magnets apart 1-2 mm from each other - so that power lines of a magnetic field were parallel planes of electrodes. The burner warm up before reception of a high-temperature flame and substitute under an aerial gap between electrodes. The arrow of the device will start to deviate slowly a zero standing, registering a current strength approximately 0,15 мА. The effect that will be stronger, than the magnetic field is stronger.

How to explain in this case occurrence electromotive force? The matter is that the burner flame represents the low-temperature plasma , consisting of plus and negatively ionised atoms of air and yields of combustion of gas (or gasoline). Ions move vertically upwards, to perpendicularly power lines. In a magnetic field on each ion Lorentz's declining an ion to an electrode the force operates. The force direction can be spotted on a left-hand rule. As a result positively ionised atoms subside on one electrode (it becomes the cathode), and subzero on other (anode). As electrodes get an opposite charge, between them arises electromotive force.

It is possible to vary not only quantity of a magnetic field. Introduction in plasma of various salt or alkaline additives also is capable to increment considerably electromotive force. And can be, children, at you will arise own original ideas in connection with this model.

Read also: MHD-GENERATOR model