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Richard:
Actually [cfr: Feynman's Lectures on Physics] it is not the acceleration of charge that produces photons (radiation), rather it is the rate of change of the acceleration of charge that results in radiation. As we all know, 'velocity' v is the rate of change of distance or space s, expressed in terms of the differential calculus this would be written in scaler form as (v = ds/dt) while 'acceleration' a is the rate of change of velocity v, (e.g. a = dv/dt = d(ds/dt)/dt). In Engineering and Physics, the next level of differential change or rate of change of acceleration is usually termed 'jerk'. Jerk j then is j = da/dt. Jerk is not often mentioned in elementary presentations of mechanics, but as far as I know even with more in depth presentations there are apparently no 'standard' terms for higher derivates of distance change than jerk. [distance, velocity, acceleration, jerk, and then...] Since, like their relative, the exponential functions, the sinusoidal functions, sine, cosine, etc... "sort of" replicate each other every time they are differentiated the higher order differentials of each such function 'look' simply like a scaled version of the other derivatives. Thus, for sinusoidal waveforms, which are the usual functional form assumed for most Engineering work, it is relatively easy for one to come up with a mathematical expression which provides exact values for radiation levels in terms of charge acceleration instead of charge jerk. Since of course if the charge velocity is sinusoidal, so is the acceleration and so is the jerk. Notwithstanding that there are well known formulas that relate radiation levels to charge acceleration for sinusoidal waveforms, it is not charge acceleration per se that causes radiation. Charge jerk causes radiation. If one desires an exact formulation for radiation caused by charge motion then perforce to be exact for general non-sinusoidal waveshapes such formulae must be related to charge jerk not acceleration. If you do not have access to Feynman' Lectures on Physics (I believe he discusses this in Vol. 3) there was a recent more accessible discussion of this topic by the editor of QEX in an article published in QEX several years ago. -- Pete k1po -- Indialantic, FL "Richard" wrote in message ... Is it not true that if I were able to accelerate my cup of coffee at light speeds at a frequency of 14Mhz my cup of coffee would radiate a 14Mhz carrier? |
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