Nonthermal continuum - terrestrial myriametric radiation narrowband electromagnetic emission

Within the past decade satellite wave-experiments discovered a nonthermal radio continuum of frequency 1-40kHz in the L-O mode permeating the magnetospheric cavity. The continuum is apparently trapped between the plasmasphere and magnetosheath, both being regions of relatively high density. The observations would appear to support best the linear mode-conversion theory of upper hydrid to L-O mode waves where the L-O radiation is emitted in a density gradient at frequencies near the plasma frequency. Thus the emission is inherently narrow-banded which prompted its renaming as terrestrial myriametric radiation (TMR). The continuum is apparently formed by multiple reflections within the magnetospheric cavity of radiation of different frequencies from different sources. Finally, the linear theory allows remote sensing of source regions by satellites. The technique has been applied with success to terrestrial myriametric and Saturnian myriametric radiations (SMR). In the former case, sources extended in magnetic latitude by as much as 10 deg about the equator are sometimes required to explain the observations. The remote sensing technique applied to Voyager 1 observations of Saturnian myriametric radiation focussed attention on L ≅ 10.6. Subsequent scrutiny of the Voyage 1 plasma data shows a steep density gradient near L ≅ 10.6, which, apparently, is believed to be the outer limit of Saturn's cold inner plasma torus. The similarity between TMR from the plasmapause and SMR from an analogous boundary at Saturn would appear to be rather striking, and its discovery possibly enhances even further the status of the linear conversion theory