Abstract
We review the inhomogeneous scalar Helmholtz equation in three-dimensions and the scattering of scalar wavefields from a scatterer of compact support. An asymptotic solution is then considered representing the effect of the frequency approaching zero when a ‘wavefield’ reduces to a ‘field’. The characteristics of ultra-low frequency Helmholtz scattering are then considered and the physical significance discussed of a model that is based on the scattering of Helmholtz wavefields over a broad frequency spectrum. This is equivalent to using a linear systems approach for modelling the propagation, interaction and detection of broad-band signals and provides an approach to the classification of a field from a wavefield that is intrinsically causal and thus, consistent with the basic principle of information theory. The approach leads to the proposal that all fields are derived from wavefields interacting over a broad frequency spectrum and that there are two principal field types: (i) fields generated by low frequency scattering - a ‘gravitational field’; (ii) fields generated by high frequency eigenfield tendency - an ‘electric field’.
| Original language | English |
|---|---|
| Pages (from-to) | 101-116 |
| Journal | ISATS Transactions on Electronics and Signal Processing |
| Volume | 1 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1 Jan 2007 |
| Externally published | Yes |
Keywords
- inhomogeneous scalar Helmholtz equation
- scattering
- ultra-low frequency
- broad frequency spectrum
- linear systems approach
- broad-band signals
- information theory
- gravitational field
- electric field