Jupiter's Decametric Radio Emission Modes

The following chart is adapted from "Physics of the Jovian Magnetosphere" published by Cambridge University Press. Other ranges have been published as one would expect with the statistical nature of these parameters. As a practical matter, however, there is a general agreement as to within a few degrees. Amateur observations should begin sometime before and end sometime after the predicted occurrences of these positions (See * note below.)

Table Headings:

MODE - Also referred to as source designation. Emissions identifiable by a unique set of parameters.

CML RANGE *- The System III Longitude of Jupiter associated with the emission. (degrees)

Io RANGE * - The position of Io relative to Superior Geocentric Conjunction, that is, the point at which Io is directly opposite from Earth with respect to Jupiter, associated with the emission. (degrees)

MAX F - Maximum observed frequency in megahertz.

POLAR - Dominant polarization of the radio wave. RH = right hand. LH = Left Hand.

ARC - Spectral arc curvature. "Late" and "Early" refer to arrival time of the vertex of the spectral feature of the emission.

* When ranges are in parentheses they are based on widths of the half maximums for the major sources as viewed from Earth at 20 MHz. Other ranges will be primarily based on Voyager observations.

MODE	CML RANGE	Io RANGE	MAX F	POLAR	ARC	NOTES
Io-D	0-200	95-130	18	LH	Early	Also called "fourth source"
Io-B	(105 - 185)	(80-110)	39.5	RH	Early	Also called "early source"
non Io-B	80-200	0-360	38	RH	Early	Voyager info
Io-A	(200-270)	(205-260)	38	RH	Late	Also called "main source"
non-Io-A	(230-280)	0-360	38	RH	Late
Io-C	(300-20)	(225-260)	36	RH&LH	Late	Also called "third source"
non-Io-C	300-360	0-360	32	RH&LH	Late	Voyager info