Properties of auroral kilometric radiation from an interferometer analysis of the ISEE-1 and -2 plasma wave data

Thesis/Dissertation · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6845741

Baumback, M M

The first satellite-satellite interferometery measurements of the auroral kilometric radiation (AKR) source region diameter are presented. By correlating the analog waveforms detected by ISEE-1 and ISEE-2, the size of the AKR source region is determined. Correlations have been measured at 125 and 250 kHz for projected baselines ranging from 20 to 3868 km. High correlations are found at all projected baselines, with little or no tendency to decrease at long baselines. The correlation is lower for events with wide bandwidths than for events with narrow bandwidths. The magnitude of the correlation as a function of signal delay and the spectra of the individual bursts show that sometimes the bandwidth of AKR bursts varies rapidly and can be narrower than 20 Hz. The spectra observed by both spacecraft are nearly identical. Correlation results are interpreted differently for incoherent radiation than for coherent radiation. If the radiation is incoherent, the visibility of the source region is the Fourier transform of the brightness distribution. Assuming incoherent radiation the average source region diameter for all analyzed bursts is less than 9.27 km. Source region diameters measured for individual bursts range from 1 to 16 km. Generation mechanisms that only amplify incoming radiation cannot produce high correlations unless the source region diameter is smaller than 25 km.

• Research Organization: Iowa Univ., Iowa City (USA)
• OSTI ID: 6845741
• Country of Publication: United States
• Language: English

Related Subjects

640201* -- Atmospheric Physics-- Auroral
Ionospheric
& Magetospheric Phenomena
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAL ZONES
COHERENT RADIATION
CORRELATIONS
ELECTROMAGNETIC RADIATION
EMISSION
FREQUENCY RANGE
KHZ RANGE
KHZ RANGE 100-1000
LONG WAVE RADIATION
PLASMA WAVES
RADIATION SOURCES
RADIATIONS
RADIOWAVE RADIATION