Practical configurations of open resonators are innumerable (e.g., Weinstein, 1969; Schulten, 1976; Auchterlonie and Ahmed, 1977). Some of the simpler cases are depicted in Figure 7. These configurations support the more interesting modes with small radiation losses. Their mode patterns can be represented by two beams of rays propagating in opposite directions without losing energy through transverse radiation. The Q-factor of a resonance is determined by radiation loss due to diffraction out of the bounding surfaces and by conduction loss within them. Open resonator Q-values are very susceptible to misalignments of the ideal geometry. High Q-values afford little tolerance to dimensional changes. For example, in the case of a plane parallel mirror pair, a deviation by as small as XQ/100 from being equidistant drops the Q-value to below 10 from the value on the order of 10,000 for a "perfect" geometry. The stringent accuracy requirements make a HSP due to open resonators unlikely. Some geometries are less sensitive (self-focusing) than others to misalignments. For example, two square («10x x 10X) aluminum sheets slightly but arbitrarily bent in a crossed cylinder arrangement had fairly high (> 10 ) Q-factors (Schiffman, 1970; see Figure 7g). 4.3. Modeling of Resonance Fields The limited time available for this study did not permit giving the modeling aspect of HSP more than a cursory glance. To remedy some of these shortcomings, the references covering relevant topics might be consulted. Modeling the field distribution of resonances in habitable space has its place to identify "worst" case situations. Since the peak value of the stored energy varies rapidly with position, calculations at a very large number of locations will be required (Safari-Naini et al., 1977). While the model should accurately describe the resonant field distribution leading to a HSP, it will also contain a lot of conjecture and simplification about the real situation. It is logical to proceed as follows: 1. Examine the possibility of resonant modes in a given structure assuming perfectly reflecting walls. 2. Consider the excitation chances for these modes via coupling to the incident field energy. 3. Introduce losses resulting (a) from imperfect specular or diffuse reflections, (b) from metallic or dielectric conduction, (c) from
RkJQdWJsaXNoZXIy MTU5NjU0Mg==