Low frequency radio emissions from Jupiter: Jovian kilometric radiation

A new component of the Jovian radio spectrum has been observed by the plasma wave instruments on Voyagers 1 and 2 at frequencies ranging from about 10 to 56 kHz or higher. This Jovian kilometric radiation is characterized by storms of emissions lasting typically 45 minutes at 56.2 kHzhowever some events persist for as long as four hours. The storms usually exhibit impulsive bursts with time scales of a few seconds to several minutesalthough some events show smoothly varying intensities as a function of time. High resolution frequency‐time spectrograms reveal a continuum‐like background with more intensenarrowband features superimposed. The narrowbandor discretefeatures tend to decrease in frequency with increasing timefalling ∼ 1 kHz in 5 to 60 seconds. The maximum power emitted assuming an isotropic radiator near Jupiter and a bandwidth for the most intense bursts of ∼ 10 kHz is about 10 9 watts. The Jovian kilometric radiation is most likely observed within ±45° of 200° System III longitudeλ III although there is a secondary maximum near λ III = 25°