11.4 Confinement of positive ions and electrons with a static electric and magnetic field

Sitemap    Calculations electromagnet

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Let's see what kind of electromagnet we need for our SEM fusor design.

length: 1 mtr
diameter: 50 cm
B = 1 tesla

B = μ0 . N/l . I   (see  hyperphysics)

N= amount of windings
μ0 = 2.10-7 NA−2

I = B . l /(μ0 . N)

N = 1000 -> I = 1 . 1 / (2.10-7  .1000) = 5000 A , vey high..

In www.gmw.com/electromagnets , amonst others, an electromagnet (coil) is sold: B= 0,13 T , DC power = 5,18 kW (140 A, 37 V), water cooling 12 ltr/min, 360 turns.  Not exactly what we need, but just to get an idea. Not enough magnetic field, consuming a lot of power and also very expensive .

Electromagnets are usually in the form of iron core solenoids, see hyperphysics .
The internal magnetic domains line up and multiplicates the field by factors to even thousands.

I think it would be better to place an electromagnet with an inner core, on top of the fusor and under the fusor (or if we turn it 90 , at the sides).

In the next link a permanent magnet, with dimensions 11x9x2 cm and a magnetic field (Remanencia Br) of 1.3 T is sold for about 120 €, see:  https://www.supermagnete.es/imanes-bloque-neodimio/bloque-magnetico-110.6mm-x-89mm-x-19.5mm-neodimio-n45-con-recubrim-epoxi_Q-111-89-20-E

Using a couple of permanents magnets?
They seem to loose rapidly strength with the distance, see: Fieldcalculator.asp
A small disk of 10 cm diameter and 1 cm thickness has at 1mm distance B= 1,4 tesla, but at  10 cm distance B=1,9 gauss, and at 30 cm B=0,1 gauss.

A small disk with the characteristics as in fig.1:

Fig.1. The magnetic field of a small neodymium magnet

If our SEM fusor had a diameter of 20 cm and a length of 0,5 m, the circumference would be 62 cm.
We could place 60 of this small magnets in a ring around. The magnet field in the middle would be 60 gauss; not enough.
The price of one such small disk is about 20 $.  ( kjmagnetics.com ). One ring would cost 1200 $. 50 rings... far to expensive.. Not an option.

I think the best idea is to contruct a vacuum chamber with our experiment and  to look for an existing magnet in, for example, an university or company. (universidad de Zaragoza?)

Or perhaps here? 



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Sitemap20 February 2014 ..     by  Rinze Joustra        www.valgetal.com