The dynamics of trapped monochromic radiation

This thesis considers a linear system constructed of monochromatic radiation trapped between end reflectors (of negligible mass) which move so that the radiation pressure, measured at the surface of the free reflector, is constant. Kinetically, the system behaves as a rigid measuring rod (which may be compared with the rigid rod suggested by W.H. McCrea) and undergoes Lorentz contraction. If a force is applied to one end while the radiation pressure and binding force maintain equilibrium, then, dynamically, the system behaves as a massive body with equivalent (inertial) rest mass. In contrast to the previous discussion by D.W. Sciama and W. Davidson on the origin of inertial forces, it is suggested that these forces are generated by a local mechanism in the extended system.

A set of three experiments demonstrates some of the properties of such a system. The first is based on an optical Michelson interferometer. One mirror is controlled by a servo unit, for which the error signal is obtained from the interference pattern, so that it tracks the movement of the other mirror and maintains a rigid length between the mirrors. The second experiment is based on a system of two trolleys with microwaves used to measure the radar distance between them. Each trolley has a separate servo control to maintain a constant distance to the other trolley. They form a dynamic system which moves independently of any reference to the laboratory. The third experiment is an electronic analogue demonstrating the time interdependence of the movements of the two ends of the system.

The second part of the thesis takes up the suggestion by R.C. Jennison that Ball Lightning may be structured entirely of electro­magnetic fields (and hence be an example of the system analysed above). Then the size of the ball of trapped waves is an indication of the frequency at which some, so far unknown, phenomenon occurs. A description is given of a preliminary experiment to investigate if there is any interaction between an electrostatic field and electro­magnetic waves of a specific frequency in the range 0.1-1 G.Hz. No evidence of such an interaction was found within the constraints of this experiment.