Abstract
The spatial distribution of whistler-mode wave emissions in the Jovian
magnetosphere measured during the first 45 perijove orbits of Juno is
investigated. A double-belt structure in whistler-mode wave intensity is
revealed. Between the two whistler-mode belts, there exists a region
devoid of 100s keV electrons near the magnetic equator at 9 <
M < 16. Insufficient source electron population in such an
electron “slot” region is a possible explanation for the relatively
lower wave activity compared to the whistler-mode belts. The wave
intensity of the outer whistler-mode belt measured in the
dusk-premidnight sector is significantly stronger than in the
postmidnight-dawn sector. We suggest that the inherent dawn-dusk
asymmetries in source electron distribution and/or auroral hiss emission
rather than the modulation of solar cycle are more likely to result in
the azimuthal variation of outer whistler-mode belt intensity during the
first 45 Juno perijove orbits.