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How many joules --> e.m. waves?



On Thu, 17 Apr 97 Alex. F. Burr wrote:

One difficulty with Kowalski's latest problem is that from an experimental
view (a view which he rightly insists upon) the initial current is 10E5
amperes which will vaporise the wire. We then have the additional
complication of a current flowing through a copper plasma. The pinch effect
will make the calculation of the radius difficult and the high magnetic
field will distort the shape.

Actually, the initial current in the LCR circuit is zero but I agree with
the above. Here is one more modification. Replace 10000 volts by 1 volt.
Then I= 1/0.1=10 A and I^2*R is only 10 W. The new wording is:

We are discharging a capacitor in the LCR circuit. Suppose that V=1 volts,
C=30 pF (15 pJ of energy is available) and that R=0.1 ohms. To simplify
assume that the wire through which the current is flowing is a circular loop
whose radius is 3 m. According to Alex's formula r=300 cm corresponds to
L=0.083 mH. How many pJ are taken away in the form of electromagnetic waves?
The setup is in the interplanetary vacuum.
Ludwik Kowalski